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Building Technologies Office

Research & Development Roadmap for Next-Generation Appliances

March 2012

i

NOTICE

This report was prepared as an account of work sponsored by an agency of the

United States Government. Neither the United States Government, nor any

agency thereof, nor any of their employees, nor any of their contractors,

subcontractors, or their employees, makes any warranty, express or implied, or

assumes any legal liability or responsibility for the accuracy, completeness, or

usefulness of any information, apparatus, product, or process disclosed, or

represents that its use would not infringe privately owned rights. Reference

herein to any specific commercial product, process, or service by trade name,

trademark, manufacturer, or otherwise, does not necessarily constitute or imply its

endorsement, recommendation, or favoring by the United States Government or

any agency, contractor or subcontractor thereof. The views and opinions of

authors expressed herein do not necessarily state or reflect those of the United

States Government or any agency thereof.

Available electronically at http://www.osti.gov/home/

http://www.osti.gov/home/

ii

Research & Development Roadmap for Next-Generation Appliances

Prepared for:

Oak Ridge National Laboratory

Oak Ridge, TN 37831

Managed by:

UT-Battelle, LLC

for the

U.S. Department of Energy

Office of Energy Efficiency and Renewable Energy

Building Technologies Office

http://www.eere.energy.gov/buildings

Prepared by:

Navigant Consulting, Inc.

77 South Bedford Street, Suite 400

Burlington, MA 01803

William Goetzler

Timothy Sutherland

Kevin Foley

March 30, 2012

http://www.eere.energy.gov/buildings

iii

Table of Contents

Table of Contents ........................................................................................................................... iii List of Figures ................................................................................................................................. v List of Tables .................................................................................................................................. v Executive Summary ....................................................................................................................... vi 1 Introduction ............................................................................................................................. 1

1.1 Background ...................................................................................................................... 1 1.2 Objective of This Roadmap.............................................................................................. 1 1.3 Roadmap Development Process ....................................................................................... 2

1.3.1 Task 1: Identify and Evaluate Potential Technical Innovations ................................... 2 1.3.2 Task 2: Define Research Needs .................................................................................... 2

1.3.3 Task 3: Create Preliminary Research & Development Roadmap ................................ 3

1.3.4 Task 4: Obtain Stakeholder Feedback .......................................................................... 3

1.4 Final Report Organization ................................................................................................ 4 2 Research and Development Roadmaps ................................................................................... 5

2.1 Refrigerator/Freezers ........................................................................................................ 5 2.1.1 Magnetic Refrigeration ............................................................................................... 10

2.1.2 Vacuum Insulation Panels .......................................................................................... 12 2.1.3 Improved Linear Compressors ................................................................................... 14 2.1.4 Stirling Cycle Refrigeration ........................................................................................ 14

2.1.5 Thermoelastic Refrigeration ....................................................................................... 15 2.1.6 Thermoelectric Refrigeration ..................................................................................... 15

2.2 Clothes Washers ............................................................................................................. 16 2.2.1 Polymer Bead Cleaning .............................................................................................. 19

2.2.2 Sanitizing Agents ........................................................................................................ 19 2.3 Clothes Dryers ................................................................................................................ 21

2.3.1 Heat Pump Clothes Dryer ........................................................................................... 26 2.3.2 Inlet Air Preheating .................................................................................................... 27 2.3.3 Mechanical Steam Compression Clothes Dryer ......................................................... 28

2.3.4 Indirect Heating (Hydronic) Clothes Dryer ................................................................ 29 2.3.5 Microwave Clothes Dryer .......................................................................................... 30

2.4 Cooking Equipment........................................................................................................ 31 2.4.1 Induction Cooktops..................................................................................................... 35 2.4.2 Specialized Cookware ................................................................................................ 35 2.4.3 Steam Cooking ........................................................................................................... 36

2.4.4 Advanced Oven Coatings ........................................................................................... 36

2.5 Cross-Cutting Technologies ........................................................................................... 37

2.5.1 Integrated Heat and Water Recovery .......................................................................... 40 3 Summary and Conclusion ..................................................................................................... 42 Appendix A Summary Tables from Previous Task Reports .................................................... 43 Appendix B Technology Readiness Level (TRL) System ...................................................... 56 Appendix C Description of Appliance Technology Options ................................................... 58

C.1 Refrigerator/Freezers ...................................................................................................... 58 C.1.1 Magnetic Refrigeration ............................................................................................... 58 C.1.2 Vacuum Insulation Panels .......................................................................................... 59

C.1.3 Improved Linear Compressors ................................................................................... 60

iv

C.1.4 Stirling Cycle Refrigeration ........................................................................................ 60

C.1.5 Thermoelastic Refrigeration ....................................................................................... 61 C.1.6 Thermoelectric Refrigeration ..................................................................................... 62

C.2 Clothes Washers ............................................................................................................. 62

C.2.1 Polymer Bead Cleaning .............................................................................................. 62 C.2.2 Sanitizing Agents ........................................................................................................ 63

C.3 Clothes Dryers ................................................................................................................ 64 C.3.1 Heat Pump Clothes Dryer ........................................................................................... 64 C.3.2 Inlet Air Pre-Heating .................................................................................................. 67

C.3.3 Mechanical Steam Compression ................................................................................ 68 C.3.4 Indirect Heating (Hydronic) Clothes Dryer ................................................................ 69 C.3.5 Microwave Clothes Dryer .......................................................................................... 70

C.4 Cooking Equipment........................................................................................................ 71

C.4.1 Induction Cooktops..................................................................................................... 71 C.4.2 Specialized Cookware ................................................................................................ 72

C.4.3 Steam Cooking ........................................................................................................... 73 C.4.4 Advanced Oven Coatings ........................................................................................... 74

C.5 Cross-Cutting Technologies ........................................................................................... 75 C.5.1 Integrated Heat & Water Recovery ............................................................................ 75

v

List of Figures

Figure 1. R&D Roadmap for Refrigerator/Freezer Technologies ................................................ xii Figure 2. R&D Roadmap for Clothes Washer Technologies ...................................................... xiii Figure 3. R&D Roadmap for Clothes Dryer Technologies ......................................................... xiv Figure 4. R&D Roadmap for Cooking Equipment Technologies................................................. xv Figure 5. R&D Roadmap for Cross-Cutting Technologies ......................................................... xvi

Figure 6. R&D Roadmap for Refrigerator/Freezer Technologies .................................................. 9 Figure 7. Work Breakdown Structure for Magnetic Refrigeration R&D Activities..................... 11 Figure 8. Work Breakdown Structures for Vacuum Insulation Panel R&D Activities ................ 13 Figure 9. R&D Roadmap for Clothes Washer Technologies ....................................................... 18 Figure 10. R&D Roadmap for Clothes Dryer Technologies ........................................................ 25

Figure 11. Work Breakdown Structure for Heat Pump Clothes Dryer R&D Activities............... 27

Figure 12. R&D Roadmap for Cooking Equipment Technologies............................................... 34

Figure 13. R&D Roadmap for Cross-Cutting Technologies ........................................................ 39 Figure 14. Work breakdown structure for integrated heat and water recovery ............................ 41

List of Tables

Table 1. Summary of R&D Recommendations for Each Appliance Technology Option ............ vii Table 2. Refrigerator/Freezers – Summary of Technology Options ............................................... 6 Table 3. Clothes Washers – Summary of Technology Options .................................................... 17

Table 4. Clothes Dryers – Summary of Technology Options ....................................................... 22 Table 5. Cooking Equipment – Summary of Technology Options .............................................. 32

Table 6. Cross-Cutting Technologies – Summary of Technology Options .................................. 38 Table 7. Task 1 - Technology Scoring Matrix .............................................................................. 43

Table 8. Task 1 - Scoring of Each Technology Option ................................................................ 44 Table 9. Task 2 – Summary of R&D Needs and Key Risks ......................................................... 45

Table 10. Task 3 - Summary of R&D Objectives, Tasks, Possible Performers, and Resources

Required ........................................................................................................................................ 48 Table 11. Task 4 - Refrigerator/Freezer Summary of Stakeholder Comments ............................ 52

Table 12. Task 4 - Clothes Washer Summary of Stakeholder Comments.................................... 53 Table 13. Task 4 - Clothes Dryer Summary of Stakeholder Comments ...................................... 54 Table 14. Task 4 - Dishwasher Summary of Stakeholder Comments .......................................... 54

Table 15. Task 4 - Cooking Equipment Summary of Stakeholder Comments ............................. 55 Table 16. Task 4 - Cross-cutting Summary of Stakeholder Comments ....................................... 55 Table 17. Technology Readiness Level (TRL) System for Categorizing Technology

Development Status ...................................................................................................................... 56

vi

Executive Summary

The Building Technologies Program (BTP) within the Department of Energy (DOE) Office of

Energy Efficiency and Renewable Energy is responsible for developing and deploying

technologies that can substantially reduce energy consumption in residential and commercial

buildings. Residential appliances such as refrigerator/freezers, dishwashers, laundry equipment,

and cooking equipment account for over 12 percent of U.S. residential sector primary energy

consumption. The appliance sector has seen substantial innovation in recent years; however,

energy efficiency measures, while significant, have generally involved incremental

improvements to meet new DOE efficiency standards. Little research has focused on radical

innovations that might dramatically reduce energy consumption. By leveraging resources, the

appliance industry may be able to work cooperatively with the DOE to develop and

commercialize products and technologies that could make dramatic improvements feasible. In

order to guide such activities and ensure the best possible outcomes, a research & development

(R&D) roadmap is necessary.

This roadmap targets high-priority R&D, demonstration, and commercialization activities that, if

pursued by DOE and its partners, could significantly reduce residential appliance energy

consumption. The roadmap prioritizes those technologies with the highest energy savings

potential and greatest likelihood of being embraced by both manufacturers and consumers. The

schedule of proposed activities ranges from near-term activities in the 6-month to 2-year time

frame, to longer-term research initiatives that may span 3-5 years or longer.

This R&D roadmap focuses on the following residential appliances: refrigerator/freezers,

clothes washers, clothes dryers, cooking equipment, and cross-cutting appliance

technologies. Microwaves and dishwashers were eliminated from consideration in this report due

to their low annual energy consumption and a lack of identified technologies that could

significantly decrease energy consumption below current best-in-class levels. This roadmap does

not cover heating, ventilation, and air-conditioning (HVAC) systems, water heaters, or building

envelope components.

Table 1. summarizes the recommended R&D activities for each technology option. Specifically,

for each technology, the table provides the following:

Summary of overall R&D objectives

Estimate of development status after achieving R&D objectives

Summary of specific R&D tasks

Identification of possible performers and their respective roles

Estimate of the duration of each R&D activity and the types of resources required

Summary of the key risks associated with each technology option

The objective of this roadmap is to advance DOE’s goal of reducing the energy

consumption of residential appliances by accelerating the commercialization of high-

efficiency appliance technologies, while maintaining the competitiveness of American

industry.

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Table 1. Summary of R&D Recommendations for Each Appliance Technology Option

Technology

Option R&D Objective

Outcomes of Achieving Objective

(TRL Advancement)1 R&D Tasks Possible Performers & Roles Duration & Resources Required Key Risks

Tier 1 (Higher Priority)

Refrigerator/

Freezer:

Magnetic

refrigeration

Demonstrate the required

cooling capacity of

residential refrigerators.

• Further understand magnetic refrigeration

cooling principles

• Optimize individual components of the

system

• Test optimized prototype to demonstrate

required cooling capacity

• BTP: provide funding, manage test

program, develop test protocols

• Ames Laboratory: expand on

previous research and prototype

Duration: 3-5 years

• Materials & supplies for component

development and system integration

• Research and development staff

• Ability to scale down components

to fit within residential-size cabinet

• Fully-functional prototype will

require years of additional R&D

• Future availability of exotic

magnetic materials

Refrigerator/

Freezer:

Vacuum insulation

panels

Understand the causes of

inconsistent results

among multiple

manufacturers’ products

and to reduce overall

costs.

• Perform characterization tests on products

known to have inconsistent performance

• Reverse-engineer products to determine

root causes for performance inconsistencies

• Analyze the supply chain of all materials

and processes used in the manufacture of

VIPs

• Determine major cost drivers and identify

strategies for reducing costs


program, perform supply chain

analysis

• Third-party laboratory: perform

energy tests using DOE test

procedure, perform reverse-

engineering analysis of VIPs

• Manufacturers: Partnership with

DOE/BT research efforts

Duration: 2-3 years

• Refrigerator/freezer products with

VIPs

• VIP samples from multiple

manufacturers

• Third-party laboratory for testing

• ORNL research staff to test and

analyze results

• Requires more costly

manufacturing methods

• Low degree of certainty on

longevity of VIPs

• Uncertain consumer willingness to

pay higher upfront cost

Clothes Dryer:

Heat pump

(electric only)

Support a pilot testing

program for pre-

commercial heat pump

clothes dryers, and

support the development

of ENERGYSTAR

criteria for heat pump

dryers.

• Support pilot testing program of pre-

commercial heat pump clothes dryers

• Support development of ENERGY STAR

criteria for high-efficiency clothes dryers

• BTP: provide technical support to

ENERGY STAR program; support

and manage pilot test program

• Manufacturers: develop technology

to pre-commercial readiness level;

collaborate with DOE on pilot test

program

• EPA: management of ENERGY

STAR program specifications

Duration: 2 years

• Funding for program technical staff

• Test equipment & materials required

for pilot testing

• Technology not yet proven for large

U.S. laundry load sizes

• Increased manufacturing cost

compared to traditional dryers



Cross-Cutting

Technologies:

Integrated energy

and water recovery

& transfer between

appliances

Measure and validate the

energy savings potential

of the ZEHcore concept

by performing laboratory

tests simulating real-

world usage patterns, and

through a pilot

demonstration project in a

residential setting.

• Develop fully functional prototype system

• Characterize system performance and

compare to modeled predictions

• Perform preliminary laboratory testing

using actual appliances

• Modify/optimize internal components

based on preliminary testing

• Further refine design to produce fully

functional prototype system

• Conduct further laboratory tests

simulating real-world usage patterns

• Conduct pilot demonstration in a

residential setting


program, manage pilot program

• ORNL: development and

refinement of ZEHcore system

• Pilot users: operate under real-

world conditions

Duration: 3-5 years

• Funding for research staff

• Materials & supplies for further

system development


for testing (including appliances)

• Funding and program support for

small-scale pilot testing

• Would require total redesign of

typical kitchen appliance layouts

• Feasibility not yet proven for

energy/water recover and transfer

concepts

• Unproven energy/water savings

• Would likely require changes to

manufacturing processes

• Uncertain consumer acceptance

• Marketing changes required to shift

away from single-appliance focus

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Technology




Tier 2 (Medium Priority)

Refrigerator/

Freezer:

Improved linear

compressor

Improve energy

efficiency of linear

compressors through

optimization of design,

material selection, and

lubricants.

• Reverse engineer commercially available

linear compressors

• Increase compressor efficiency through

improved designs, materials, and lubricants

to optimize performance

• Test optimized compressor to

demonstrate improved energy efficiency


program


reverse-engineering analysis

• National Laboratory: design and

testing

Duration: 2 years • Materials to build and test improved

compressors

• Research staff to build, test, and

analyze compressors

• May involve proprietary

compressor designs

Clothes Washer:

Polymer bead

cleaning

Demonstrate technology

viability in commercial-

scale laundry facilities;


of a prototype for

residential use, and assess

any environmental or

safety hazards.

• Support pilot testing program of

commercial-scale washers at on-premise

and off-premise laundry facilities

• Support ongoing development of a

residential prototype that would be relevant

in the U.S. market

• Demonstrate residential prototype

functionality under laboratory conditions

• Assess any environmental risks or safety

hazards associated with polymer beads in a


• Xeros, Ltd: manufacturer of pilot

test units and prototypes, cooperation

with DOE project

• BTP: provide funding, coordinate

pilot test program, manage R&D of

residential prototypes

• National Laboratory: cooperative

R&D agreement with manufacturer;

funding & support for development

of residential prototype

• Large-scale gas utility: coordinate

pilot test program of commercial-

scale units

Duration: 3-5 years

• BTP project staff to manage test

program

• National Laboratory staff for

prototype development and testing

• Funding and program support for

pilot testing of commercial-scale units

• Suitability of technology for

residential laundry not yet

demonstrated

• Cleaning ability of technology not

yet proven to AHAM standards

• Uncertain consumer acceptance of

new plastic particle technology

• Potential environmental and safety

concerns associated with polymer

beads

Clothes Dryer:

Inlet air preheat

Adapt currently available

technology to residential

clothes dryers, determine

the energy-savings

potential, and assess the

viability of inlet air

preheating technology for

residential clothes dryers.

• Develop smaller-scale design that could

be applicable to residential dryers

• Modify residential clothes dryer cabinet

with air inlets/outlets to work with heat

wheel technology

• Perform testing to determine energy

savings potential

• Investigate the feasibility of installing

heat exchanger inside dryer cabinet

• BTP: provide funding, manage

R&D program


build prototype system, perform

prototype testing

• Rototherm Corp.: provide samples

of current heat wheel technology,

cooperate and/or collaborate with

DOE project

Duration: 1 year


• Materials & supplies for developing

modified components


for internal testing

• Unproven energy savings potential





• Potential impacts on installation

procedures

• Potential safety issues with lint

handling

Clothes Dryer:

Mechanical steam

compression

(electric only)

Validate the technology

concept by developing a

complete working

prototype and performing

testing under laboratory

conditions.

• Develop remaining components required

for fully functional system

• Integrate components to develop

functional prototype



• BTP: provide funding, monitor

R&D progress

• Center for Energy Studies, Ecole

des Mines de Paris (Mines

ParisTech): expand on previous

research and prototypes

• U.S. university or National

Laboratory: joint research activities

with Center for Energy Studies

Duration: 2 years





for testing

• Technology not yet proven in

integrated prototype




compared to heat pump dryers with

little or no additional benefit



1 2 3 4 5 6 7 8 9

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0 1 2 3

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0 1 2 3

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0 1 2 3

ix

Technology




Cooking

Equipment:

Induction cooktops

Verify energy savings,

incorporate into DOE’s

cooking equipment test

procedure, and support

the development of an

ENERGY STAR

specification for

cooktops.

• Test commercially available units to

determine energy savings potential

• Create test method to incorporate into the

DOE test procedure


criteria for cooktops




energy tests

• EPA: Management of ENERGY


Duration: 1 year

• Procurement of units for testing


• Requires specialized cookware

• Uncertainty regarding wide-scale

consumer demand for this technology

• Unverified energy savings in real-

world residential settings

Cooking

Equipment:

Specialized

cookware

Quantify the energy

savings potential and


of an ENERGY STAR

specification for

specialized cookware.

• Perform energy testing of commercially

available products to verify energy

efficiency potential.






energy tests

• Cookware manufacturers: assist in

developing ENERGY STAR

specifications

• EPA: Management of ENERGY


Duration: 1 year




consumer demand for specialty

cookware

• Unverified energy savings in real-

world residential settings

Tier 3 (Lower Priority)

Refrigerator/

Freezer:

Stirling cycle

refrigeration

Determine the energy

savings potential of

stirling cycle

refrigerator/freezers by

developing and testing a

working prototype.

• Create a full-sized residential prototype

• Determine energy performance



• Conduct further testing



• Purdue University: provide

knowledge and expertise on stirling

cycle refrigeration R&D

Duration: 2-3 years

• Research staff to develop and test

prototype

• Materials required to build prototype


compared to vapor-compression

systems

• Challenges regarding how to

transfer heat away from refrigerated

compartments

Refrigerator/

Freezer:

Thermoelastic

refrigeration

Demonstrate the cooling

capacity that would be

required for a residential

refrigerator.

• Further understand thermoelastic

refrigeration cooling principles


system





• University of Maryland: expand on


development

Duration: 3-5 years



• University of Maryland research

staff to test and analyze results

• Concept is proven, but low degree

of certainty that the technology is

feasible in a residential setting



transfer heat away from refrigerated

compartments

Refrigerator/

Freezer:

Thermoelectric

refrigeration

Determine the potential

energy savings of a full-

sized residential

thermoelectric

refrigerator/freezer by

developing prototypes for

laboratory testing.










• National Laboratory: design,

testing, and development of

prototypes

Duration: 2-3 years

• Small thermoelectric refrigerators to

analyze

• Materials to build full-sized

prototype

• Research staff to build, test, and

analyze prototypes


compared to vapor-compression

refrigeration

• Uncertainty regarding ability to

scale up manufacturing process

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2

x

Technology




Clothes Washer:

Sanitizing agents

Assess environmental and

health risks of certain

sanitizing agents that

would enable lower-

temperature wash cycles.

• Assess environmental risks associated

with wastewater discharge of sanitizing

agents

• Assess human health risks associated with

certain sanitizing agents

• BTP: provide funding, coordination

of environmental and health

assessments

• EPA: coordination and review of

environmental and health

assessments

Duration: 1 year

• BTP project staff to manage program

• Funding for environmental and

health assessments

• Certain sanitizing agents may pose

environmental or human health risks

• Perceived risks may limit consumer

acceptance

• Perceived risks and potential

liability concerns may limit

manufacturer interest

Clothes Dryer:

Indirect heating



indirect (hydronic)

clothes dryer technology

with back-to-back dryer

cycles.

• Procure several working units

• Perform testing of back-to-back dryer

cycles

• Determine energy savings potential

• Assess any risks associated with clothing

cool-down period

• Hydromatics Technologies: provide

units for testing



• Third-party accredited laboratory:

perform energy & performance tests

• DOE Standards team: provide

background/insights, help evaluate

test results

Duration: 6 months



program


• DOE Standards staff to help analyze

results






• Lack of a cool-down phase before

the load comes to rest could pose a

safety hazard

Clothes Dryer:

Microwave

(electric only)

Assess various methods

for alleviating major

safety concerns, and

develop a working

prototype for laboratory

testing.

• Investigate feasibility of eliminating

major safety concerns

• Refine previous prototype models to

address safety concerns

• Demonstrate testing under laboratory

conditions

• BTP: provide funding, manage

R&D program


build prototype system, perform pilot

testing

• Manufacturers: collaborate with

DOE to leverage prior design and

testing experience

Duration: 2-3 years


• Materials & supplies for prototype

development


for internal testing

• Potential safety issues associated

with metal zippers, coins, and other

metallic objects






microwave dryer technology 1 Black fill numbers indicate current TRL status; grey fill numbers indicate target TRL status after achieving the overall R&D objective. See Appendix B for details on the TRL system.

: Current TRL status

: Target TRL status after R&D activities

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#

#

xi

The following sections summarize the R&D roadmaps for each appliance type. For technologies

with time-sensitive R&D tasks, the timelines are shown on a fiscal year (FY) basis beginning

with FY 2012. For technologies with R&D tasks that are less sensitive to the absolute date, the

R&D timelines are shown on a relative year basis, beginning at Year 0.

Refrigerator/Freezers

The technologies with the greatest potential for improving energy efficiency are those that can

generate the required amount of cooling more efficiently than traditional vapor-compression

systems, as well as technologies that help reduce the amount of heat transfer into the refrigerated

food compartments. Figure 1 shows the finalized R&D roadmaps for refrigerator/freezer

technologies. The roadmap shows the various recommended technology options identified for

refrigerator/freezers, as well as estimated timelines for each task.

xii

Figure 1. R&D Roadmap for Refrigerator/Freezer Technologies

Clothes Washers

MAGNETIC REFRIGERATION

REFRIGERATORS/FREEZERS

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019

VACUUM INSULATION PANELS

FY2020

FY2020

MORE EFFICIENT COMPRESSOR TECHNOLOGIES

3

99

9 9

99

Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6


Year 7

Year 7

STIRLING CYCLE

5

4

LEGEND

High or medium priority activity

Low priority activity

Analysis

Design & Development

Testing & Validation

PRIORITY RATINGTIMELINE

Pilot Program

Market Incentive Program

Likely future follow-on activity

#

Technology Readiness Level

6

THERMOELECTRIC REFRIGERATION

4 6

THERMOELASTIC REFRIGERATION

3 4

(ENGINEERING ANALYSIS PROGRAM)

(SUPPLY CHAIN ANALYSIS PROGRAM)

xiii

The technologies with the greatest potential for improving energy efficiency are those that enable

lower water temperatures and/or less overall hot water consumption. Figure 2 shows the finalized

R&D roadmaps for clothes washer technologies. The roadmap shows the two recommended

technology options identified for clothes dryers, as well as estimated timelines for each task.

Figure 2. R&D Roadmap for Clothes Washer Technologies

POLYMER BEAD CLEANING

CLOTHES WASHERS

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019 FY2020


(COMMERCIAL-SCALE PILOT TEST PROGRAM)

(RESIDENTIAL PROTOTYPE

DESIGN PROGRAM)5

7 8

6

Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7


SANITIZING AGENTS

LEGEND



Analysis




Pilot Program



#


9 9

xiv

Clothes Dryers

The technologies with the greatest potential for improving energy efficiency are those that

provide more efficient methods for creating heat as well as technologies that help reduce the

amount of wasted heat. Figure 3 shows the finalized R&D roadmaps for clothes dryer

technologies. The roadmap shows the various recommended technology options identified for

clothes dryers, as well as estimated timelines for each task.

Figure 3. R&D Roadmap for Clothes Dryer Technologies

CLOTHES DRYERS

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

HEAT PUMP DRYING

INDIRECT (HYDRONIC) HEATING

(PILOT TEST PROGRAM)7

7 9 (ENERGY STAR SUPPORT)

9

INLET AIR PRE-HEATING

3 5

MECHANICAL STEAM COMPRESSION

4 5

Year 0 Year 2 Year 4Year 1 Year 3 Year 5


MICROWAVE DRYING

7 8

9 9

LEGEND



Analysis




Pilot Program



#


xv

Cooking Equipment

The technologies with the greatest potential for improving energy efficiency are those that use

more efficient means for generating heat, as well as technologies that help improve heat transfer

to the cooking vessel or directly to the food. Figure 4 shows the finalized R&D roadmaps for

cooking technologies. The roadmap shows the various recommended technology options

identified for cooking equipment, as well as estimated timelines for each task.

Figure 4. R&D Roadmap for Cooking Equipment Technologies

COOKING EQUIPMENT

FY2013 FY2014 FY2015

FY2013 FY2014 FY2015 FY2016 FY2017

Year 0 Year 1 Year 2

Year 0 Year 1 Year 2 Year 3 Year 4

SPECIALIZED COOKWARE

9 9

INDUCTION COOKTOPS

9 9

LEGEND



Analysis




Pilot Program



#


xvi

Cross-Cutting Appliance Technologies

Cross-cutting technologies are those technologies that offer the potential for integrated energy

and water recovery and/or transfer between appliances. For example, waste heat from a

refrigerator could be used to preheat the incoming water for the dishwasher; similarly, latent heat

from a clothes dryer exhaust vent could be used to preheat incoming water for the clothes

washer. Figure 5 shows the finalized R&D roadmap for cross-cutting appliance technologies.

The roadmap shows the estimated timelines for each R&D task.

Figure 5. R&D Roadmap for Cross-Cutting Technologies

INTEGRATED HEAT & WATER RECOVERY

CROSS-CUTTING

Year 0 Year 1 Year 2 Year 3 Year 4 Year 5


LEGEND



Analysis




Pilot Program



#


5 7

1

1 Introduction

1.1 Background

The Building Technologies Program (BTP) within the Department of Energy (DOE) Office of

Energy Efficiency and Renewable Energy is responsible for developing and deploying

technologies that can substantially reduce energy consumption in residential and commercial

buildings. Activities in recent years have included technical pathways to achieve net zero energy

homes. Most recently, particular attention has been focused on energy savings potential in

existing buildings, because the impacts are more immediate due to the slow turnover of the

residential building stock. Because appliances are less expensive and are replaced more regularly

than heating, ventilation, and air-conditioning (HVAC) systems or building envelope

components, they present an opportunity for near-term energy savings.

Residential appliances such as refrigerator/freezers, dishwashers, laundry equipment, and

cooking equipment account for over 12 percent of U.S. residential sector primary energy

consumption. The appliance sector has seen substantial innovation in recent years; however,

energy efficiency measures, while significant, have generally involved incremental

improvements to meet new DOE efficiency standards. Little research has focused on radical

innovations that might dramatically reduce energy consumption. By leveraging resources, the

appliance industry may be able to work cooperatively with the DOE to develop and

commercialize products and technologies that could make significant improvements feasible. In

order to guide such activities and ensure the best possible outcomes, a research & development

(R&D) roadmap is necessary.

1.2 Objective of This Roadmap

This roadmap targets high-priority R&D, demonstration, and commercialization activities that, if

pursued by DOE and its partners, could significantly reduce residential appliance energy

consumption. The roadmap prioritizes those technologies with the highest energy savings

potential and greatest likelihood of being embraced by both manufacturers and consumers. The

schedule of proposed activities ranges from near-term activities in the 6-month to 2-year time

frame, to longer-term research initiatives that may span 3-5 years.

This R&D roadmap focuses on the following residential appliances: refrigerator/freezers,

clothes washers, clothes dryers, cooking equipment, and cross-cutting appliance

technologies. This roadmap does not cover heating, ventilation, and air-conditioning (HVAC)

systems, water heaters, or building envelope components.

The objective of this roadmap is to advance DOE’s goal of reducing the energy

consumption of residential appliances by accelerating the commercialization of high-

efficiency appliance technologies, while maintaining the competitiveness of American

industry.

2

1.3 Roadmap Development Process

This R&D roadmap was developed by Navigant Consulting, Inc., in cooperation with Oak Ridge

National Laboratory (ORNL). The following provides a summary of each task completed during

the process of developing this roadmap:

1.3.1 Task 1: Identify and Evaluate Potential Technical Innovations

Objectives

In Task 1, we determined which appliances should be included in our assessment and identified

possible technical innovations that could be applied to improve energy efficiency. We then

completed a preliminary feasibility assessment of each identified technology and evaluated

performance and approximate cost relative to today’s baseline equipment.

Approach

Through literature searches and discussions with industry experts, we identified technology

options for each appliance. Next, we applied a preliminary screening to eliminate technologies

that offered only incremental improvements in energy efficiency. The remaining technologies

included only those that could provide significant improvements in appliance energy efficiency.

We then developed a set of scoring criteria to further evaluate the remaining technology options.

The criteria included technical energy savings potential, fit with DOE/BT mission, cost and

complexity, and non-energy benefits. We assigned a weighting factor to each criterion to reflect

its relative importance. Using a 1–5 scale, we rated each technology option against each criterion

and calculated an overall rating score. We used the quantitative scoring and other qualitative

considerations to assess the feasibility of each technology option and to prioritize each option for

further in-depth analysis.

Conclusions

The analysis indicated that the appliances with the best combination of high energy savings

potential and strong fit with the DOE/BT mission are refrigerator/freezers, clothes washers,

clothes dryers, and cross-cutting appliance technologies.

The analysis indicated that cooktops, ovens, microwaves, and dishwashers had relatively little

national energy savings potential, although some of the technology options could be a strong fit

with the DOE/BT mission. In addition, the annual energy cost to the consumer is so low for these

appliances that even a moderate increase in appliance cost would likely have an unacceptably

long payback period.

1.3.2 Task 2: Define Research Needs

Objectives

In Task 2, we defined the research and development needs to be addressed in order to accelerate

commercialization of each of the down-selected technology options identified in Task 1. We

also prioritized these research and development needs.

Approach

To help facilitate planning, we first prioritized the technology options into tiers using the scoring

results from Task 1. Next, we reviewed additional literature and held additional discussions with

industry experts to determine the current state of each technology option. We then categorized

3

the current state of each technology option using the Technology Readiness Level (TRL) system.

Based on the current TRL status, we then determined the research and development needs of

each technology option that, if supported, would help accelerate its commercialization. We also

determined the key risks associated with each technology option.

Conclusions

The results from Task 2 reaffirmed the preliminary conclusions from Task 1; specifically, that

the appliance categories with the highest-priority, highest energy savings potential, and strongest

fit with the DOE/BT mission are refrigerator/freezers, clothes washers, clothes dryers, and

cross-cutting appliance technologies.

The analysis confirmed that cooktops, ovens, and dishwashers are lower priority with relatively

little national energy savings potential, although some of the technology options have a

moderately strong or very strong fit with the DOE/BT mission.

1.3.3 Task 3: Create Preliminary Research & Development Roadmap

Objectives

In Task 3, we created a preliminary R&D roadmap for each appliance technology with goals and

timetables, priorities, identification of possible performers and their respective roles, and a

relative comparison of the resources required to achieve the goals.

Approach

Using the R&D needs identified in Task 2, we first defined the overall R&D objective for each

technology option. Next, we determined the R&D tasks that would be required to achieve each

objective. We then identified possible performers and their respective R&D roles for each

technology option. We also estimated the approximate duration and resources required to achieve

the R&D objectives for each technology option. Finally, we created preliminary research and

development roadmaps for each appliance technology and developed work breakdown structures

for the highest-priority technology options.

Conclusions

The R&D roadmaps developed during Task 3 provided a foundation for discussions with key

stakeholders during Task 4.

1.3.4 Task 4: Obtain Stakeholder Feedback

Objectives

In Task 4, we obtained feedback on the preliminary R&D roadmaps from key stakeholders such

as manufacturers, national laboratories, and industry experts.

Approach

We conducted a series of one-on-one discussions with key stakeholders to review the preliminary

roadmaps for each appliance technology. We received feedback from manufacturers

representing over 85 percent of the core major appliances1 market. Due to the sensitive nature of

R&D programs, private discussions with manufacturers were conducted under non-disclosure

agreements. In addition, we interviewed home appliance industry experts and lead researchers

who are involved with some of the high-priority technology options identified in the roadmaps.

1 Core major appliances include refrigerator/freezers, clothes washers, clothes dryers, dishwashers, and ranges.

4

Conclusions

Stakeholders generally expressed the strongest interest in refrigerator/freezer and clothes dryer

technologies, and moderate interest in clothes washer technologies. Stakeholders generally

expressed little interest in dishwasher and cooking equipment technologies due to the limited

energy savings potential and the unlikelihood of consumer acceptance of those particular

technologies.

1.4 Final Report Organization

This final report is organized as follows:

Section 2 presents the finalized R&D roadmaps for each appliance type. This section

provides a brief summary description of each appliance technology, a description of the

R&D needs, and a discussion of the proposed R&D activities.

Section 3 provides a brief summary and conclusions from this roadmap effort.

Appendix A provides the key summary tables from previous task reports.

Appendix B provides a description of the Technology Readiness Level (TRL) system

referenced throughout the report.

Appendix C provides detailed technical descriptions of each technology option, including

current development status and links to relevant source information.

5

2 Research and Development Roadmaps

The following sections present the research and development roadmaps for each appliance type.

Each roadmap highlights the activities that, with DOE support, would accelerate the

commercialization of each technology. DOE support may involve any combination of financial,

technical, or programmatic resources. Each section contains a table summarizing the

recommended R&D activities for each technology option. Specifically, for each technology, the

table provides the following:

Summary of overall R&D objectives

Estimate of development status after achieving R&D objectives

Summary of specific R&D tasks

Identification of possible performers and their respective roles

Estimate of duration of each R&D activity and types of resources required

Summary of key risks associated with each technology option

The roadmaps include two categories of technologies: The first category includes technologies

with time-sensitive R&D tasks. For these technologies, the timelines are shown on a fiscal year

(FY) basis beginning with FY 2012. The second category includes technologies with R&D tasks

that are less time-sensitive (i.e., less sensitive to the absolute date when the activities would

begin). For these technologies, the R&D timelines are shown on a relative year basis, beginning

with Year 0.

2.1 Refrigerator/Freezers

The primary driver of energy consumption in refrigerator/freezers is the energy required to

power the vapor-compression cycle, which uses a compressor and multiple heat exchangers to

transfer heat from inside the food compartments to outside the refrigerator/freezer. Accordingly,

the technologies with the greatest potential for improving energy efficiency are those that can

generate the required amount of cooling more efficiently than traditional vapor-compression

systems, as well as technologies that greatly reduce the amount of heat transfer between the walls

of the refrigerated food compartments.

Table 2 summarizes the recommended R&D objectives and tasks identified for the highest-

potential refrigerator/freezer technologies, possible performers and their respective roles, and

estimated duration of each R&D activity.

6

Table 2. Refrigerator/Freezers – Summary of Technology Options

Technology





Refrigerator/

Freezer:

Magnetic

refrigeration

Demonstrate the required

cooling capacity of



cooling principles


system





• Ames Laboratory: expand on previous

research and prototype

Duration: 3-5 years



• Research and development staff

• Ability to scale down

components to fit within

residential-size cabinet

• Fully-functional prototype

will require years of additional

R&D

• Future availability of exotic

magnetic materials

Refrigerator/

Freezer:

Vacuum

insulation panels

Understand the causes of

inconsistent results among

multiple manufacturers’

products and to reduce

overall costs.







VIPs




program, perform supply chain analysis

• Third-party laboratory: perform energy

tests using DOE test procedure, perform

reverse-engineering analysis of VIPs



Duration: 2-3 years

• Refrigerator/freezer products with VIPs

• VIP samples from multiple manufacturers


• ORNL research staff to test and analyze

results

• Requires more costly

manufacturing methods

• Low degree of certainty on

longevity of VIPs

• Uncertain consumer

willingness to pay higher

upfront cost


Refrigerator/

Freezer:

Improved linear

compressor

Improve energy efficiency

of linear compressors

through optimization of

design, material selection,

and lubricants.

• Reverse engineer commercially available

linear compressors

• Increase compressor efficiency through

improved designs, materials, and lubricants to

optimize performance

• Test optimized compressor to demonstrate

improved energy efficiency


program


reverse-engineering analysis


testing

Duration: 2 years • Materials to build and test improved

compressors

• Research staff to build, test, and analyze

compressors

• May involve proprietary

compressor designs


Refrigerator/

Freezer:

Stirling cycle

refrigeration



stirling cycle

refrigerator/freezers by

developing and testing a

working prototype.



• Modify/optimize internal components based

on preliminary testing




• Purdue University: provide knowledge

and expertise on stirling cycle

refrigeration R&D

Duration: 2-3 years

• Research staff to develop and test

prototype


• Unproven energy savings

potential compared to vapor-

compression systems


transfer heat away from

refrigerated compartments

Refrigerator/

Freezer:

Thermoelastic

refrigeration

Demonstrate the cooling

capacity that would be

required for a residential

refrigerator.

• Further understand thermoelastic

refrigeration cooling principles


system





• University of Maryland: expand on


development

Duration: 3-5 years



• University of Maryland research staff to

test and analyze results

• Concept is proven, but low

degree of certainty that the

technology is feasible in a

residential setting


potential


transfer heat away from

refrigerated compartments

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

7

Technology




Refrigerator/

Freezer:

Thermoelectric

refrigeration

Determine the potential

energy savings of a full-

sized residential

thermoelectric

refrigerator/freezer by


laboratory testing.










• National Laboratory: design, testing,

and development of prototypes

Duration: 2-3 years

• Small thermoelectric refrigerators to

analyze

• Materials to build full-sized prototype

• Research staff to build, test, and analyze

prototypes


potential compared to vapor-

compression refrigeration

• Uncertainty regarding ability

to scale up manufacturing

process

1 Black fill numbers indicate current TRL status; grey fill numbers indicate target TRL status after achieving the overall R&D objective. See Appendix B for details on the TRL system.



1 2 3 4 5 6 7 8 9

0 1 2

#

#

8

Figure 6 shows the finalized R&D roadmap for refrigerator/freezer technologies. The roadmap

shows the various recommended technology options identified for refrigerator/freezers, as well

as estimated timelines for each task. For technologies with time-sensitive R&D tasks, the

timelines are shown on a fiscal year basis beginning with FY 2012. For technologies with R&D

tasks that are less time-sensitive (i.e., less sensitive to the absolute date on which the activities

would begin), the R&D timelines are shown on a relative year basis, beginning with Year 0.

9

Figure 6. R&D Roadmap for Refrigerator/Freezer Technologies

MAGNETIC REFRIGERATION

REFRIGERATORS/FREEZERS

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019

VACUUM INSULATION PANELS

FY2020

FY2020

MORE EFFICIENT COMPRESSOR TECHNOLOGIES

3

99

9 9

99



Year 7

Year 7

STIRLING CYCLE

5

4

LEGEND



Analysis




Pilot Program



#


6

THERMOELECTRIC REFRIGERATION

4 6

THERMOELASTIC REFRIGERATION

3 4

(ENGINEERING ANALYSIS PROGRAM)

(SUPPLY CHAIN ANALYSIS PROGRAM)

10

The following sections provide additional details regarding our recommended R&D activities

for each of these refrigerator/freezer technologies. Target work breakdown structures (WBS) are

also provided for the highest-priority technologies.

2.1.1 Magnetic Refrigeration

Magnetic refrigeration is based on the magneto-caloric effect, in which changing magnetic

fields are used to create a reversible change in temperature of a paramagnetic material. A

working prototype has been developed at the Ames Laboratory. However, due to the size of the

components and the high magnetic field required, the system is not applicable for use in

residential settings. Additionally, existing prototypes do not yet demonstrate the cooling

performance required for a residential refrigerator/freezer. This technology is currently at

TRL 3.

The recommended R&D activities include a multi-year program to further understand the

principles of magnetic cooling, optimize individual components of the system, and demonstrate

the required cooling capacity of a residential refrigerator/freezer. In the long-term, magnetic

refrigeration shows the potential to be a viable replacement for traditional vapor-compression

systems, with greater energy efficiency. Therefore, this is a high-priority technology option that

DOE should continue to support over the next several fiscal years. Many more years of

additional R&D will be required to create a fully functional residential magnetic

refrigerator/freezer.

The recommended program of research and component development could advance this

technology to TRL 4.

Figure 7 shows a target WBS for magnetic refrigeration development.

Magnetic Refrigeration

Priority: High

Current Status: Concept of magnetic refrigeration is proven and a working

prototype has been built.

R&D Objective: Demonstrate the cooling capacity that would be required for a

residential refrigerator.

Recommended R&D Activities:

o Further understand magnetic refrigeration cooling principles

o Optimize individual components of the system

o Test optimized prototype to demonstrate required cooling capacity

Program Duration: 3-5 years

11

Figure 7. Work Breakdown Structure for Magnetic Refrigeration R&D Activities

TASK 1

REVIEW RESULTS FROM PREVIOUS STUDIES

MILESTONE 1 (SEPTEMBER 2013): DEVELOP IMPROVED KNOWLEDGE OF MAGNETIC REFRIGERATION

REVIEW OF TASK 1 PROGRESS

TASK 2

ANALYZE MODELS AND TEST RESULTS TO FURTHER UNDERSTAND FUNDAMENTAL PRINCIPLES OF MAGNETIC COOLING

REFINE INDIVIDUAL COMPONENTS OF PREVIOUS PROTOTYPES

MILESTONE 2 (SEPTEMBER 2015): DEVELOP WORKING PROTOTYPE


TASK 3

TASK 1: STUDY MAGNETIC

COOLING PRINCIPLES

TASK 2: IMPROVE INDIVIDUAL

COMPONENTS

CONDUCT LABORATORY TESTS ON PROTOTYPE

DEMONSTRATE REQUIRED COOLING CAPACITY

MILESTONE 3 (MARCH 2016): REPORT DETAILING DEMONSTRATION OF REQUIRED COOLING CAPACITY

TASK 3: TESTING

WORK BREAKDOWN STRUCTURE: MAGNETIC REFRIGERATION

FY2013 FY2014 FY2015 FY2016

FY2013 FY2014 FY2015 FY2016 FY2017

ASSEMBLE COMPONENTS TO CREATE WORKING PROTOTYPE

FY2017

1

1

2

2

3

3

12

2.1.2 Vacuum Insulation Panels

Vacuum-insulated panel (VIP) technology is based on the reduction in conductivity that occurs

in a low vacuum. VIPs used in refrigeration products consist of a sealed package with a fill

material that provides support to prevent the panel from collapsing and interferes with the

molecular mean free path, as the intermolecular spacing increases at lower vacuum levels. VIPs

are currently commercially available, but their performance is inconsistent among

manufacturers. In addition, the cost is substantial compared to traditional insulation techniques.

Currently, this technology is at TRL 9.

The first recommended R&D program includes a testing and reverse-engineering program to

identify the root causes of performance inconsistencies in VIPs. The second recommended

program is an analysis of the manufacturing supply chain for VIPs to identify the primary

drivers of cost and to implement strategies for cost reduction.

By improving reliability and lowering the cost, these recommended programs would keep VIP

technology at TRL 9 and would significantly increase the prevalence of this technology option

in the residential refrigerator/freezer market. Because VIPs have the potential to significantly

improve energy efficiency in the short-term, this is a high-priority technology option that DOE

should continue to support over the next few fiscal years.

Figure 8 shows a target WBS for VIP research activities.

Vacuum Insulation Panels

Priority: High

Current Status: VIPs are commercially available from some manufacturers.

R&D Objective: Understand the causes of inconsistent results among

manufacturers’ products and reduce overall costs.


o Perform characterization tests on products known to have inconsistent

performance

o Determine root causes for performance inconsistencies

o Analyze the supply chain of all materials and processes used in the

manufacture of VIPs

o Determine major cost drivers and identify strategies for reducing costs


13

Figure 8. Work Breakdown Structures for Vacuum Insulation Panel R&D Activities

WORK BREAKDOWN STRUCTURE: VACUUM INSULATION PANELS (VIP) –ENGINEERING ANALYSIS PROGRAM

TASK 1

IDENTIFY PRODUCTS WITH VIP CONSTRUCTION

FY2014 FY2015

PERFORM ENERGY TESTING OF VIP PRODUCTS

MILESTONE 1 (APRIL 2014): LABORATORY TEST RESULTS


TASK 2

MILESTONE 2 (DECEMBER 2015): REPORT IDENTIFYING LIKELY CAUSES OF PERFORMANCE INCONSISTENCIES IN VIPS

TASK 1: PERFORM TESTING OF PRODUCTS

WITH VIPS

TASK 2: PERFORM

REVERSE-ENGINEERING ANALYSIS

PERFORM REVERSE ENGINEERING ANALYSIS

FY2014FY2015

1

1

2

2

CONDUCT ADDITIONAL LABORATORY TESTING TO DETERMINE ROOT CAUSES OF PERFORMANCE INCONSISTENCIES

TASK 1

IDENTIFY MAJOR DRIVERS OF COST THROUGHOUT SUPPLY CHAIN

MILESTONE 1 (SEPTEMBER 2013): REPORT DOCUMENTING FINDINGS


TASK 2

PERFORM ANALYSIS OF SUPPLY CHAIN FOR ALL MATERIALS AND PROCESSES IN VIP PRODUCTION

DEVELOP STRATEGIES FOR REDUCING MAJOR DRIVERS OF COST

MILESTONE 2 (DECEMBER 2014): DEMONSTRATE COST SAVINGS IN VIP SUPPLY CHAIN

TASK 1:ANALYZE SUPPLY CHAIN

TASK 2: DEVELOP COST

REDUCTION STRATEGIES

FY2014

IMPLEMENT COST SAVING STRATEGIES

FY2015

1

1

FY2016 FY2017

FY2014 FY2016FY2015 FY2017

WORK BREAKDOWN STRUCTURE: VACUUM INSULATION PANELS (VIP) –SUPPLY CHAIN ANALYSIS PROGRAM

2

2

14

2.1.3 Improved Linear Compressors

Linear compressors employ a different design than either reciprocating or rotary compressors

and are reportedly more efficient than both. Linear compressors use a linear rather than rotary

motor, thus eliminating the crankshaft and linkage that converts the rotary motion to the linear

motion of the piston of a reciprocating compressor. High efficiency linear compressors exist on

the market, but could benefit from improved design, materials, and lubricants. Currently, this

technology is at TRL 9.

In the short-term, the improvement of compressor technologies can increase the energy

efficiency of traditional vapor-compression systems. The recommended R&D program includes

developing and testing an optimized compressor to demonstrate improved energy efficiency

over currently available products.

These R&D activities would help keep linear compressor technology at TRL 9 and could

significantly increase the prevalence of this technology option in the refrigerator/freezer market.

2.1.4 Stirling Cycle Refrigeration

A Stirling cycle machine is a device that operates on a closed regenerative thermodynamic

cycle, with cyclic compression and expansion of the working fluid at different temperature

levels. The flow of the working fluid is controlled by volume changes, so that there is a net

conversion of heat to work, or vice versa. A Stirling refrigeration cycle compresses and expands

an inert gas in a single cylinder. Heat is rejected at one end of the cylinder and absorbed at the

opposite end. In the absence of all thermodynamic losses, the efficiency could be higher than for

vapor compression systems. Various technical difficulties have so far limited the use of Stirling

cycle cooling to small prototype residential refrigerators. Currently, this technology is at TRL 5.

Stirling cycle technology is well known, but has not been shown to be more efficient than vapor

compression. Thus, manufacturers have not pursued this technology. The recommended R&D

program includes developing and testing a full-sized residential prototype.

This recommended R&D program could advance Stirling cycle refrigeration to TRL 6.

Improved Linear Compressors

Priority: Medium

Current Status: More efficient compressors are commercially available from some

manufacturers.

R&D Objective: Improve energy efficiency of linear compressors through optimization of

design, material selection, and lubricants.

Potential R&D Activities:

o Reverse engineer commercially available linear compressors

o Increase compressor efficiency through improved designs, materials, and

lubricants to optimize performance

o Test optimized compressor to demonstrate improved energy efficiency

Program Duration: 2 years

15

2.1.5 Thermoelastic Refrigeration

Thermoelastic cooling is based on a thermoelastic shape memory alloy that releases heat when

compressed and returns to its original shape when heated. Researchers are developing a 0.01-ton

prototype with the goal of establishing the commercial viability of thermoelastic cooling.

Currently, this technology is at TRL 3.

The recommended R&D program includes refining individual components to improve the

cooling capacity. Many years of research will be required to create a full-size residential

refrigerator/freezer using thermoelastic cooling technology.

These R&D activities could advance thermoelastic refrigeration technology to TRL 4.

2.1.6 Thermoelectric Refrigeration

Thermoelectric cooling occurs when a current is passed across the junction of two dissimilar

metals. One side of the device becomes hot and the other becomes cold. Several compact

refrigerators and wine coolers using thermoelectric cooling are currently available on the

market, including several models offered by Avanti Products. However, their efficiency is lower

than traditional vapor-compression models, and the technology is not yet suitable for standard-

Stirling Cycle Refrigeration

Priority: Low

Current Status: Working prototypes have been developed, but limited to small


R&D Objective: Determine the energy savings potential of a Stirling cycle refrigerator by

developing and testing a working prototype.


o Create a full-sized residential prototype

o Determine energy performance

o Modify/optimize internal components based on preliminary testing

o Conduct further testing


Thermoelastic Refrigeration

Priority: Low

Current Status: Concept has been proven, and a prototype is being developed.

R&D Objective: Demonstrate the cooling capacity required for a residential

refrigerator/freezer.


o Further understand thermoelastic refrigeration cooling principles

o Optimize individual components of the system

o Test optimized prototype to demonstrate required cooling capacity


16

size residential refrigerator-freezers. Therefore, for standard-size refrigerator/freezers, we

consider this technology to be at TRL 4.

The recommended R&D program includes development of a full-sized prototype, energy

performance testing, and additional design and development based on preliminary test results.

This R&D program could advance this technology to TRL 6 for full-size residential

refrigerator/freezers.

2.2 Clothes Washers

The primary driver of energy consumption in residential clothes washers is the energy required

to heat the hot water. The machine electrical energy represents less than one quarter of total

energy consumption. Accordingly, the technologies with the greatest potential for improving

energy efficiency are those that enable lower water temperatures and/or less overall hot water

consumption.


potential clothes washer technologies, possible performers and their respective roles, and

estimated duration of each R&D activity.

Thermoelectric Refrigeration

Priority: Low

Current Status: Small thermoelectric refrigerators are commercially available from

some manufacturers.

R&D Objective: Determine the energy savings potential (if any) of a full-sized

residential thermoelectric refrigerator/freezer by developing prototypes for

laboratory testing.


o Create a full-sized residential prototype

o Determine energy performance

o Modify/optimize internal components based on preliminary testing

o Conduct further testing


17

Table 3. Clothes Washers – Summary of Technology Options

Technology Option R&D Objective Outcomes of Achieving Objective



(none)


Clothes Washer:

Polymer bead

cleaning

Demonstrate technology

viability in commercial-scale

laundry facilities; support

the development of a

prototype for residential use,

and assess any

environmental or safety

hazards.

• Support pilot testing program of commercial-

scale washers at on-premise and off-premise

laundry facilities

• Support ongoing development of a residential

prototype that would be relevant in the U.S.

market

• Demonstrate residential prototype

functionality under laboratory conditions

• Assess any environmental risks or safety

hazards associated with polymer beads in a


• Xeros, Ltd: manufacturer of pilot test

units and prototypes, cooperation with

DOE project

• BTP: provide funding, coordinate pilot

test program, manage R&D of residential

prototypes

• National Laboratory: cooperative R&D

agreement with manufacturer; funding &

support for development of residential

prototype

• Large-scale gas utility: coordinate pilot

test program of commercial-scale units

Duration: 3-5 years


program

• National Laboratory staff for prototype

development and testing

• Funding and program support for pilot

testing of commercial-scale units

• Suitability of technology for residential

laundry not yet demonstrated

• Cleaning ability of technology not yet

proven to AHAM standards

• Uncertain consumer acceptance of new

plastic particle technology

• Potential environmental and safety

concerns associated with polymer beads


Clothes Washer:

Sanitizing agents

Assess environmental and

health risks of certain

sanitizing agents that would

enable lower-temperature

wash cycles.

• Assess environmental risks associated with

wastewater discharge of sanitizing agents

• Assess human health risks associated with

certain sanitizing agents

• BTP: provide funding, coordination of

environmental and health assessments

• EPA: coordination and review of

environmental and health assessments

Duration: 1 year

• BTP project staff to manage program

• Funding for environmental and health

assessments

• Certain sanitizing agents may pose

environmental or human health risks

• Perceived risks may limit consumer

acceptance

• Perceived risks and potential liability

concerns may limit manufacturer interest 1

Black fill numbers indicate current TRL status; grey fill numbers indicate target TRL status after achieving the overall R&D objective. See Appendix B for details on the TRL system.



1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

#

#

18

Figure 9 shows the finalized R&D roadmaps for clothes washer technologies. The roadmap

shows the two recommended technology options identified for clothes dryers, as well as

estimated timelines for each task. For technologies with time-sensitive R&D tasks, the timelines

are shown on a fiscal year (FY) basis beginning with FY 2012. For technologies with R&D tasks

that are less sensitive to the absolute date, the R&D timelines are shown on a relative year basis,

beginning at Year 0.

Figure 9. R&D Roadmap for Clothes Washer Technologies

The following sections provide additional details regarding our recommended R&D activities for

each of these clothes washer technologies.

POLYMER BEAD CLEANING

CLOTHES WASHERS



(COMMERCIAL-SCALE PILOT TEST PROGRAM)

(RESIDENTIAL PROTOTYPE

DESIGN PROGRAM)5

7 8

6



SANITIZING AGENTS

LEGEND



Analysis




Pilot Program



#


9 9

19

2.2.1 Polymer Bead Cleaning

Polymer bead cleaning technology is currently in development by Xeros Ltd. in the United

Kingdom. Xeros Ltd. has successfully concluded two field trials of this technology: One field

study was in a commercial-scale dry cleaning setting and the other was in an industrial laundry

setting. Development is ongoing to create prototypes for residential use. For clothes washers in a

residential setting, this technology is currently at TRL 5.

The recommended R&D program includes supporting future pilot testing program of

commercial-scale washers at on-premise and off-premise laundry facilities in the U.S. To

accelerate the development of this technology for residential application, we recommend creatine

a cooperative research agreement with the manufacturer to support the ongoing development of a

residential prototype that would be relevant to the U.S. laundry consumers. This R&D effort

would culminate in the demonstration of a residential prototype under laboratory conditions. In

addition, we recommend investigating any environmental or human health and safety risks

associated with the usage and disposal of polymer beads in a residential setting.

This recommended R&D program could advance the state of this technology for residential

settings to TRL 6.

2.2.2 Sanitizing Agents

Certain sanitizing agents, such as chemical or ionic compounds, can be added to the incoming

cold wash water to reduce the need for hot water washing. A clothes washer using such

sanitizing agents could offer cooler wash cycles that provide sanitization of the clothing; such

wash cycles typically require hot water temperatures up to 140°F.

Polymer Bead Cleaning

Priority: Medium

Current Status: Pilot tests have been performed at commercial-scale laundry

facilities in the UK; development of a residential prototype is ongoing.

R&D Objective: Demonstrate viability in commercial-scale laundry facilities in the

U.S., support the development of a prototype for residential use, and assess any

environmental or safety hazards.


o Support pilot testing program of commercial-scale washers at on-premise

and off-premise laundry facilities in the U.S.

o Support ongoing development of a residential prototype that would be

relevant in the U.S. market.

o Demonstrate residential prototype functionality under laboratory conditions.

o Assess any environmental risks or safety hazards associated with the usage

and disposal of polymer beads in a residential setting.


20

One example of a sanitizing agent is the addition of silver ions to the cold wash water. Silver is a

natural disinfectant and can provide sanitization during a cold water wash. Samsung previously

introduced this technology to the market; therefore, this technology is at TRL 9. However,

concerns about potential health and environmental risks arose after these clothes washers entered

the market. This technology has since been withdrawn from the market.

The recommended R&D program includes assessing the environmental and human health risks

associated with silver ion and other sanitizing agents that may be added to the wash water. The

assessment would include an investigation of the risks associated with sanitizing agents in

wastewater discharge. This recommended research program could alleviate concerns associated

with various sanitizing agents and could help promote the usage of cold water wash cycles.

This recommended research program could allow this technology to remain at TRL 9 and enable

cold-water sanitizing agents to be reintroduced to the market by any interested manufacturer.

Sanitizing Agents

Priority: Low

Current Status: Previously available on the market, but since withdrawn.

R&D Objective: Assess the environmental and health risks of certain sanitizing

agents that would enable the usage of lower-temperature wash cycles.


o Assess environmental risks associated with wastewater discharge of

sanitizing agents.

o Assess human health risks associated with certain sanitizing agents.

Program Duration: 1 year

21

2.3 Clothes Dryers

The primary driver of energy consumption in residential clothes dryers is the energy required to

heat the air inside the drum. Accordingly, the technologies with the greatest potential for

improving energy efficiency are those that provide more efficient methods for creating heat as

well as technologies that help reduce the amount of wasted heat.


potential clothes dryer technologies, possible performers and their respective roles, and estimated

duration of each R&D activity.

22

Table 4. Clothes Dryers – Summary of Technology Options




Clothes Dryer:

Heat pump

(electric only)

Support a pilot testing

program for pre-commercial

heat pump clothes dryers,

and support the development

of ENERGYSTAR criteria

for heat pump dryers.

• Support pilot testing program of pre-

commercial heat pump clothes dryers


criteria for high-efficiency clothes dryers

• BTP: provide technical support to

ENERGY STAR program; support and

manage pilot test program

• Manufacturers: develop technology to

pre-commercial readiness level;

collaborate with DOE on pilot test

program

• EPA: management of ENERGY STAR

program specifications

Duration: 2 years

• Funding for program technical staff

• Test equipment & materials required for

pilot testing

• Technology not yet proven for large

U.S. laundry load sizes

• Increased manufacturing cost compared

to traditional dryers

• Uncertain consumer willingness to pay

higher upfront cost


Clothes Dryer:

Inlet air preheat

Adapt currently available

technology to residential

clothes dryers, determine the

energy-savings potential,

and assess the viability of

inlet air preheating

technology for residential

clothes dryers.

• Develop smaller-scale design that could be

applicable to residential dryers

• Modify residential clothes dryer cabinet with

air inlets/outlets to work with heat wheel

technology

• Perform testing to determine energy savings

potential

• Investigate the feasibility of installing heat

exchanger inside dryer cabinet

• BTP: provide funding, manage R&D

program

• National Laboratory: design and build

prototype system, perform prototype

testing

• Rototherm Corp.: provide samples of

current heat wheel technology, cooperate

and/or collaborate with DOE project

Duration: 1 year


• Materials & supplies for developing

modified components


internal testing





higher upfront cost

• Potential impacts on installation

procedures

• Potential safety issues with lint

handling

Clothes Dryer:

Mechanical steam

compression

(electric only)

Validate the technology

concept by developing a

complete working prototype

and performing testing under

laboratory conditions.

• Develop remaining components required for

fully functional system

• Integrate components to develop functional

prototype

• Characterize system performance and compare

to modeled predictions

• BTP: provide funding, monitor R&D

progress

• Center for Energy Studies, Ecole des

Mines de Paris (Mines ParisTech):

expand on previous research and

prototypes

• U.S. university or National Laboratory:

joint research activities with Center for

Energy Studies

Duration: 2 years





testing

• Technology not yet proven in integrated

prototype




to heat pump dryers with little or no

additional benefit


higher upfront cost


Clothes Dryer:

Indirect heating


savings potential of indirect

(hydronic) clothes dryer

technology with back-to-

back dryer cycles.


• Perform testing of back-to-back dryer cycles


• Assess any risks associated with clothing

cool-down period

• Hydromatics Technologies: provide

units for testing



• Third-party accredited laboratory:

perform energy & performance tests


background/insights, help evaluate test

results

Duration: 6 months



program


• DOE Standards staff to help analyze

results





higher upfront cost

• Lack of a cool-down phase before the

load comes to rest could pose a safety

hazard

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

23



Clothes Dryer:

Microwave

(electric only)

Assess various methods for

alleviating major safety

concerns, and develop a

working prototype for

laboratory testing.

• Investigate feasibility of eliminating major

safety concerns

• Refine previous prototype models to address

safety concerns

• Demonstrate testing under laboratory

conditions


program

• National Laboratory: design and build

prototype system, perform pilot testing

• Manufacturers: collaborate with DOE

to leverage prior design and testing

experience

Duration: 2-3 years


• Materials & supplies for prototype

development


internal testing

• Potential safety issues associated with

metal zippers, coins, and other metallic

objects




higher upfront cost


microwave dryer technology 1




1 2 3 4 5 6 7 8 9

0 1 2 3

#

#

24

Figure 10 shows the finalized R&D roadmaps for clothes dryer technologies. The roadmap

shows the various recommended technology options identified for clothes dryers, as well as

estimated timelines for each task. For technologies with time-sensitive R&D tasks, the timelines

are shown on a fiscal year (FY) basis beginning with FY 2012. For technologies with R&D

tasks that are less sensitive to the absolute date, the R&D timelines are shown on a relative year

basis, beginning at Year 0.

25

Figure 10. R&D Roadmap for Clothes Dryer Technologies

CLOTHES DRYERS

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

FY2013 FY2014 FY2015 FY2016 FY2017 FY2018

HEAT PUMP DRYING

INDIRECT (HYDRONIC) HEATING

(PILOT TEST PROGRAM)7

7 9 (ENERGY STAR SUPPORT)

9

INLET AIR PRE-HEATING

3 5

MECHANICAL STEAM COMPRESSION

4 5



MICROWAVE DRYING

7 8

9 9

LEGEND



Analysis




Pilot Program



#


26


for each of these clothes dryer technologies. A target work breakdown structure (WBS) is also

provided for the pilot test program for heat pump drying, which is the highest-priority

technology for clothes dryers.

2.3.1 Heat Pump Clothes Dryer

Several prototype heat pump clothes dryers have been developed previously through DOE

funding and partnerships. Heat pump dryers have been on the market in Europe for several

years; however, heat pump dryers are not currently unavailable in the U.S. It is widely expected

that heat pump dryers will become commercially available in the U.S. in the near future. This

technology is currently at TRL 7.

The recommended program involves providing program support and funding for pilot testing of

pre-commercial heat pump dryer demonstration units. A pilot demonstration program would

allow manufacturers to understand consumer usage habits and any address any technical hurdles

that might remain before wide-scale commercial availability.

In anticipation of entry into the market, the Environmental Protection Agency (EPA) has chosen

advanced clothes dryers as one of the ENERGY STAR Emerging Technology Award categories

for 20122. It is anticipated that heat pump technology would be one of the few clothes dryer

technologies able to achieve the energy factor requirements established by ENERGY STAR.

We recommend that DOE continue to provide support to ENERGY STAR clothes dryer

initiatives to help accelerate the commercialization and consumer adoption of heat pump clothes

dryers when they become commercially available.

These recommended testing and program activities could advance heat pump dryer technology

to TRL 9.

2 More information on the ENERGY STAR 2012 Emerging Technology Award for Advanced Clothes Dryers can be found at

the program’s website: http://www.energystar.gov/index.cfm?c=pt_awards.pt_clothes_dryers

Heat Pump Clothes Dryer

Priority: High

Current Status: Working prototypes have been developed; technology available in

Europe but not yet available in the U.S.

R&D Objective: Support a pilot testing program for pre-commercial heat pump

clothes dryers, and support the development of ENERGYSTAR criteria for heat

pump dryers.


o Support pre-commercial pilot testing program with manufacturer

collaboration.

o Support EPA/DOE development of ENERGY STAR criteria for clothes

dryers.


http://www.energystar.gov/index.cfm?c=pt_awards.pt_clothes_dryers

27

Figure 11 shows a target WBS for the pilot test program for heat pump clothes dryer

development.

Figure 11. Work Breakdown Structure for Heat Pump Clothes Dryer R&D Activities

2.3.2 Inlet Air Preheating

One company, Rototherm Corporation, has developed a heat recovery wheel that provides dryer

inlet air preheating in a commercial laundry setting. Limited testing has been performed to

provide energy savings estimates in a commercial setting. However, we are unaware of any

adaptations of this technology for use with residential clothes dryers. Therefore, currently, this

technology is at TRL 3 for residential clothes dryers.

The recommended R&D program includes developing a smaller-scale version of the heat

recovery wheel that could be applied to residential clothes dryers. The external cabinet of a

residential clothes dryer would be modified with an air inlet to be compatible with the heat

wheel. The prototype system would be tested to determine the energy savings potential of heat

wheel technology in a residential setting. Further design work could be performed to investigate

the feasibility of installing the heat exchange system inside the dryer cabinet.

TASK 1

OBTAIN NECESSARY TESTING APPROVALS

MILESTONE 1 (MARCH 2013): PILOT TEST PLAN APPROVED

INITIATE PLANNING FOR PILOT TEST PROGRAM

TASK 1:PLANNING

WORK BREAKDOWN STRUCTURE: HEAT PUMP CLOTHES DRYER – PILOT TEST

PROGRAM

FY2013 FY2014 FY2015

1

FY2013 FY2014 FY2015 FY2016

TASK 2:PILOT TESTING


TASK 2

MILESTONE 2 (SEPTEMBER 2015): COMPLETION OF PILOT TESTING

CONDUCT PILOT TEST PROGRAM IN RESIDENTIAL HOUSEHOLDS

2

COLLECT RELEVANT MACHINE DATA, CONSUMER USAGE DATA, AND USER FEEDBACK

FY2016

TASK 3:ANALYSIS

21 3


TASK 3

MILESTONE 3 (DECEMBER 2015): REPORT DESCRIBING RESULTS OF PILOT TESTING PROGRAM AND RECOMMENDATIONS

ANALYZE RESULTS OF PILOT TESTING PROGRAM

3

PROVIDE INSIGHTS AND RECOMMENDATIONS FOR FULL COMMERCIALIZATION

28

This recommended program of prototype development could advance inlet air preheating

technology to TRL 5.

2.3.3 Mechanical Steam Compression Clothes Dryer

The Center for Energy Studies (CES) in Paris, France has developed a super-heated steam dryer

concept using mechanical steam compression. The CES has completed preliminary performance

testing on a compressor that could be used in such a system. Computer simulations have been

conducted to model the performance of a complete working system; however, we are unaware

of any fully-assembled working laboratory prototype. Currently, this technology is at TRL 4.

The recommended R&D program includes development of the remaining components required

in the system, integration into a fully functional prototype, and preliminary energy performance

testing. Because the laboratory developing this technology is located in France, a cooperative

research agreement would need to be reached with a national laboratory or academic institution

in the U.S.

This recommended program of research and prototype development could advance mechanical

steam compressor drying technology to TRL 5.

Inlet Air Preheating

Priority: Medium

Current Status: Technology available for commercial laundry setting, but not for

residential clothes dryers.

R&D Objective: Adapt currently available technology to residential clothes dryers,

determine the energy-savings potential, and assess the viability of inlet air

preheating technology for residential clothes dryers.


o Develop smaller-scale design that could be applicable to residential dryers.

o Modify residential clothes dryer cabinet with air inlets/outlets to be

compatible with heat wheel technology.

o Perform testing to determine energy savings potential.

o Investigate the feasibility of installing heat wheel system inside dryer

cabinet.


29

2.3.4 Indirect Heating (Hydronic) Clothes Dryer

Hydromatics Technologies Corp. has developed a hydronic heating system for electric dryers,

marketed under the Safe-Mates brand. The company claims that its clothes dryer uses 50 percent

less energy compared to a conventional clothes dryer; however, these estimates have not been

independently confirmed. In addition, the hydronic dryer may benefit from back-to-back

laundry cycles, which are not accounted for in the DOE energy efficiency test procedure. This

technology is currently at TRL 9.

The recommended program involves conducting testing to evaluate the energy savings potential

of this technology when back-to-back laundry cycles are conducted. This testing program would

resolve specific questions that arose during the most recent energy efficiency standards

rulemaking for clothes dryers. In addition, an assessment would be made of any potential safety

risks associated with the clothing cool-down period. Lack of an adequate cool-down period

could pose a fire hazard.

This recommended testing program could allow this technology to remain at TRL 9 and would

help resolve outstanding questions regarding the energy savings potential of indirect (hydronic)

clothes dryer technology.

Mechanical Steam Compression Clothes Dryer

Priority: Medium

Current Status: Individual components have been developed; fully working

prototype not yet developed.

R&D Objective: Validate the technology concept by developing a working

prototype and performing testing under laboratory conditions.


o Develop remaining components required for fully functional system.

o Integrate components to develop functional prototype.

o Characterize system performance and compare to modeled predictions.


30

2.3.5 Microwave Clothes Dryer

Previous research by the Electric Power Research Institute (EPRI) led to the development and

testing of prototype microwave dryers. Serious safety concerns were raised due to electrical

arcing between metallic objects in the microwave dryer. EPRI investigated some approaches to

mitigating the risk of arcing; however, the persistence of safety concerns has resulted in the

abandonment of any major R&D activities related to microwave drying. This technology is

currently at TRL 7.

The recommended R&D program includes investigating techniques for eliminating the major

safety concerns associated with microwave clothes drying, such as through the use of advanced

sensors or by creating a hybrid system that combines microwave drying with traditional drying.

If the major safety concerns can be resolved, R&D efforts would continue with the development

of demonstration units that could be tested in a pilot test program in residential settings.

This recommended program of research and prototype development could advance microwave

clothes drying TRL 8.

Indirect Heating (Hydronic) Clothes Dryer

Priority: Low

Current Status: Technology is commercially available, but energy savings

potential is unverified.

R&D Objective: Determine the energy savings potential associated with back-to-

back drying cycles using hydronic clothes dryer technology.


o Procure several working units from manufacturer.

o Perform testing of back-to-back dryer cycles.

o Determine energy savings potential.

o Assess any risks associated with clothing cool-down period.

Program Duration: 6 months

Microwave Clothes Dryer

Priority: Low

Current Status: Prototypes have been developed previously, but safety concerns

remain the key barrier to further development.

R&D Objective: Assess various methods for alleviating major safety concerns, and

develop a working prototype for laboratory testing.


o Investigate the feasibility of eliminating major safety concerns.

o Refine previous prototype models to address safety concerns.

o Demonstrate successful testing under laboratory conditions.


31

2.4 Cooking Equipment

The primary driver of energy consumption in cooking equipment is the generation of heat and

the subsequent transfer of heat from the heat source to the cooking vessel and the food.

Accordingly, the technologies with the greatest potential for improving energy efficiency are

those that can generate heat more efficiently, as well as technologies that help improve heat

transfer to the cooking vessel or directly to the food.


potential cooking technologies, possible performers and their respective roles, and estimated

duration of each R&D activity.

32

Table 5. Cooking Equipment – Summary of Technology Options




(none)


Cooking

Equipment:

Induction cooktops

Verify energy savings,

incorporate into DOE’s

cooking equipment test

procedure, and support the

development of an

ENERGY STAR

specification for cooktops.

• Test commercially available units to

determine energy savings potential

• Create test method to incorporate into the

DOE test procedure






tests

• EPA: Management of ENERGY STAR


Duration: 1 year



• Requires specialized cookware


consumer demand for this technology

• Unverified energy savings in real-world

residential settings

Cooking

Equipment:

Specialized

cookware

Quantify the energy savings

potential and support the

development of an

ENERGY STAR

specification for specialized

cookware.

• Perform energy testing of

commercially available products to

verify energy efficiency potential.

• Support development of ENERGY

STAR criteria for cooktops




tests

• Cookware manufacturers: assist in

developing ENERGY STAR

specifications

• EPA: Management of ENERGY STAR


Duration: 1 year




consumer demand for specialty

cookware

• Unverified energy savings in real-world

residential settings


(none) 1




1 2 3 4 5 6 7 8 9

0 1 2 3

1 2 3 4 5 6 7 8 9

0 1 2 3

#

#

33

Figure 12 shows the finalized R&D roadmaps for cooking technologies. The roadmap shows the

various recommended technology options identified for cooking equipment, as well as estimated

timelines for each task. For technologies with time-sensitive R&D tasks, the timelines are

shown on a fiscal year (FY) basis beginning with FY 2012. For technologies with R&D tasks

that are less sensitive to the absolute date, the R&D timelines are shown on a relative year basis,


34

Figure 12. R&D Roadmap for Cooking Equipment Technologies


for each of these cooking equipment technologies.

COOKING EQUIPMENT

FY2013 FY2014 FY2015

FY2013 FY2014 FY2015 FY2016 FY2017

Year 0 Year 1 Year 2

Year 0 Year 1 Year 2 Year 3 Year 4

SPECIALIZED COOKWARE

9 9

INDUCTION COOKTOPS

9 9

LEGEND



Analysis




Pilot Program



#


35

2.4.1 Induction Cooktops

Induction cooktops uses an inductor and the creation of magnetic fields to generate heat from

specialized cooking vessels. Induction cooktops are currently available on the market; therefore,

this technology is at TRL 9. Although induction cooktops are significantly more efficient than

both gas and electric cooktops, the technology is not accommodated by the current DOE test

procedure for cooking equipment.

The recommended activities include testing commercially available units to verify expected

energy savings, creating a test method to incorporate into the DOE test procedure, and

supporting the development of an ENERGY STAR rating for residential cooktops.

These recommended programs would keep induction cooktop technology at TRL 9 and could

significantly increase the prevalence of this technology in the residential cooking equipment

market.

2.4.2 Specialized Cookware

Cookware modified with fins or grooves along the bottom surface have been shown to

significantly increase cooktop efficiency. Heat-up times are substantially reduced and

production capacities increased. Eneron, Inc. has developed two unique pot designs that use

aluminum fins to increase the surface area exposed to the burner flame, thereby increasing the

rate of heat transfer to the bottom of the pot. This technology is currently at TRL 9.

This type of cookware may also be well-suited for commercial cooking applications, where

larger quantities of food are prepared and the annual energy consumption of the cooking

equipment is much more substantial.

The recommended program involves quantifying the energy efficiency potential of specialized

cookware in a residential setting, and supporting the development of an ENERGY STAR

specification for specialized cookware.

These activities would keep specialized cookware technology at TRL 9 and could significantly

increase the prevalence of this technology in the residential cookware market.

Induction Cooking

Priority: Medium

Current Status: Induction cooktops are commercially available from some

manufacturers.

R&D Objective: Verify energy savings potential, incorporate into the DOE cooking

equipment test procedure, and support the development of an ENERGY STAR

specification for residential cooktops.


o Test commercially available units to determine energy savings potential

o Create test method to incorporate into the DOE test procedure

o Support development of ENERGY STAR criteria for cooktops


36

2.4.3 Steam Cooking

With steam cooking, energy is transferred to the food load by means of the condensation of

steam on the food surface. This may occur at essentially atmospheric pressure, or the cavity may

be pressurized in order to allow higher steam temperatures and thus higher energy transfer to the

food. Ovens with steam cooking capabilities are available on the market; thus, this technology is

currently at TRL 9.

In the Task 4 report, we had proposed keeping steam cooking as one of the recommended

technologies for DOE to support. However, after additional analysis and discussion with

industry experts, we have removed steam cooking from consideration. The energy savings

potential is incremental compared to traditional oven cooking, and the technology would likely

be used infrequently due to U.S. consumers’ food and cooking preferences.

2.4.4 Advanced Oven Coatings

The self-cleaning cycle in an oven uses approximately 17% of the total annual energy

consumption (assuming four self-clean cycles per year). Innovative oven coatings could reduce

the energy consumption of the self-clean cycle by releasing food particles at lower temperatures.

The reduced self-clean temperatures would thus reduce the annual energy consumption of self-

clean ovens.

In the Task 4 report, we had proposed adding advanced oven coatings as one of the

recommended technologies for DOE to support. However, after additional literature review, we

discovered that Maytag recently introduced an advanced oven coating, marketed under tha name

“AquaLift,” that requires much lower self-cleaning temperatures (200°F rather than 800°F for a

traditional self-clean cycle). Because this technology has already been commercialized by a

major manufacturer, and its energy saving benefits are well-understood, we do not believe there

is an appropriate role for DOE in further development of this technology. Therefore, we have

removed advanced oven coatings from consideration.

Specialized Cookware

Priority: Medium

Current Status: Specialized cookware is commercially available.

R&D Objective: Quantify the energy savings potential and support the

development of an ENERGY STAR specification for specialized cookware.


o Perform energy testing of commercially available products to verify energy

efficiency potential.

o Support development of ENERGY STAR criteria for cooktops.


37

2.5 Cross-Cutting Technologies

Cross-cutting technologies are those technologies that offer the potential for integrated energy

and water recovery and/or transfer between appliances. For example, waste heat from a

refrigerator could be used to preheat the incoming water for a dishwasher; similarly, latent heat

from a clothes dryer exhaust vent could be used to preheat incoming water for a clothes washer.


potential cross-cutting appliance technologies, possible performers and their respective roles,

and estimated duration of each R&D activity.

38

Table 6. Cross-Cutting Technologies – Summary of Technology Options




Cross-Cutting

Technologies:

Integrated energy

and water recovery

& transfer between

appliances

Measure and validate the

energy savings potential of

the ZEHcore concept by

performing laboratory tests

simulating real-world usage

patterns, and through a pilot



• Develop fully functional prototype system



• Perform preliminary laboratory testing using

actual appliances





• Conduct further laboratory tests simulating

real-world usage patterns

• Conduct pilot demonstration in a residential

setting


program, manage pilot program

• ORNL: development and refinement of

ZEHcore system

• Pilot users: operate under real-world

conditions

Duration: 3-5 years


• Materials & supplies for further system

development


testing (including appliances)

• Funding and program support for small-

scale pilot testing

• Would require total redesign of typical

kitchen appliance layouts

• Feasibility not yet proven for

energy/water recover and transfer

concepts


• Would likely require changes to

manufacturing processes


• Marketing changes required to shift

away from single-appliance focus


(none)


(none) 1




1 2 3 4 5 6 7 8 9

0 1 2 3

#

#

39

Figure 13 shows the finalized R&D roadmap for cross-cutting appliance technologies. The

roadmap shows the estimated timelines for each R&D task. The development of this technology

is not particularly time-sensitive, so the R&D timelines are shown on a relative year basis,


Figure 13. R&D Roadmap for Cross-Cutting Technologies

The following section provides additional details regarding our recommended R&D activities

for cross-cutting appliance technologies.

INTEGRATED HEAT & WATER RECOVERY

CROSS-CUTTING



LEGEND



Analysis




Pilot Program



#


5 7

40

2.5.1 Integrated Heat and Water Recovery

ORNL has developed a ZEHcor Interior Utility Wall concept designed to reduce hot water

distribution losses and enable a high level of integration between appliances. The ZEHcore wall

concept is a pre-fabricated wall to which all kitchen and laundry appliances would be connected,

including major bathroom fixtures. Currently, this technology is at TRL 5.

The recommended R&D program includes laboratory testing with simulated and actual

appliances, additional design and development, and a pilot demonstration program. This R&D

program could advance this technology to TRL 7.

Figure 14 shows a target WBS for further development of integrated heat and water recovery

technology.

Integrated Heat and Water Recovery

Priority: High

Current Status: Prototype integrated wall concept has been developed; technology

still in early development stages.

R&D Objective: Measure and validate the energy savings potential of the ZEHcore

concept by performing laboratory tests simulating real-world usage patterns, and

through a pilot demonstration project in a residential setting.


o Develop fully functional prototype system.

o Characterize system performance and compare to modeled predictions.

o Perform preliminary laboratory testing using actual appliances.

o Modify/optimize internal components based on preliminary testing.

o Conduct further laboratory tests simulating real-world usage patterns.

o Conduct pilot demonstration in a residential setting


41

Figure 14. Work breakdown structure for integrated heat and water recovery

TASK 1

REPLICATE OR PROCURE ZEHCORE PROTOTYPE WALL SYSTEM

CHARACTERIZE HEAT TRANSFER & WATER RECOVERY PERFORMANCE

MILESTONE 1 (SEPTEMBER 2013): REPORT DOCUMENTING ENERGY & WATER SAVINGS OF PRELIMINARY PROTOTYPE SYSTEM


TASK 2

INSTALL “DUMMY” APPLIANCES TO SIMULATE WATER & ENERGY USAGE PATTERNS

REPLACE DUMMY APPLIANCES WITH REAL APPLIANCES

MILESTONE 2 (JUNE 2014): REPORT DOCUMENTING ENERGY & WATER SAVINGS OF FUNCTIONING PROTOTYPE SYSTEM


TASK 3

TASK 1: CHARACTERIZE

PROTOTYPE

PERFORMANCE

TASK 2: APPLIANCE

TESTS

MODIFY & OPTIMIZE PROTOTYPE DESIGN BASED ON PRELIMINARY TEST RESULTS

PERFORM FOLLOW-ON TESTING TO MEASURE PERFORMANCE IMPROVEMENTS

MILESTONE 3 (JUNE 2015): REPORT DOCUMENTING ENERGY & WATER SAVINGS OF OPTIMIZED PROTOTYPE SYSTEM

WORK BREAKDOWN STRUCTURE: INTEGRATED HEAT & WATER RECOVERY

FY2013 FY2014 FY2015 FY2016

TEST PROTOTYPE SYSTEM UNDER TYPICAL USAGE

FY2017

1

1

2

3

CHARACTERIZE HEAT TRANSFER & WATER RECOVERY PERFORMANCE USING REAL APPLIANCES

TASK 3:PROTOTYPE MODIFICATIONS &

FOLLOW-ON TESTING

2TASK 4:PILOT

DEMONSTRATION

3 4

TASK 4

INSTALL OPTIMIZED PROTOTYPE SYSTEM IN PRE-FABRICATED RESIDENTIAL DWELLINGS

MEASURE ENERGY & WATER CONSUMPTION FOR A PERIOD OF ONE YEAR

MILESTONE 4 (JUNE 2016): REPORT DOCUMENTING ENERGY & WATER SAVINGS OF FULLY INTEGRATED PILOT SYSTEM

4


COMPARE ENERGY & WATER CONSUMPTION TO SIMILAR RESIDENTIAL DWELLING WITH TRADITIONAL APPLIANCE HOOKUPS

FY2013 FY2014 FY2015 FY2016 FY2017

42

3 Summary and Conclusion

The appliance R&D roadmaps presented in this report target high-priority R&D, demonstration,

and commercialization activities that, if pursued by DOE and its partners, could significantly

reduce residential appliance energy consumption. The roadmap prioritizes those technologies

with the highest energy savings potential and greatest likelihood of being embraced by both

manufacturers and consumers.

The results of our study indicate that the appliance categories with the highest-priority, highest

energy savings potential, and strongest fit with the DOE/BT mission are refrigerator/freezers,

clothes washers, clothes dryers, and cross-cutting appliance technologies.

The analysis showed that cooking equipment appliances are lower priority with relatively little

national energy savings potential, although some of the technology options would have a

moderately strong or very strong fit with the DOE/BT mission.

The R&D roadmaps presented in this report will advance DOE’s goal of reducing energy

consumption of residential appliances by accelerating the commercialization of high-efficiency

appliance technologies, while maintaining the competitiveness of American industry.

43

Appendix A Summary Tables from Previous Task Reports

This Appendix provides the key summary tables from previous task reports.

Table 7. Task 1 - Technology Scoring Matrix

Screening Criteria

Wt.

Factor

Score

1 2 3 4 5

Technical Energy

Savings Potential 35%

< 100

TBtu/yr

100 – 300

TBtu/yr

300 – 500

TBtu/yr

500 – 700

TBtu/yr > 700 TBtu/yr

Fit with DOE/BT

Mission 35% Very weak fit

Moderately

weak fit

Neither strong

nor weak fit

Moderately

strong fit

Very strong

fit

Cost/Complexity 15%

Much higher

cost/

complexity

Moderately

higher cost/

complexity

Slightly

higher cost/

complexity

Potential for

similar cost/

complexity

Potential for

lower cost/

complexity

Other Non-

Energy Benefits 15%

Potential

negative

effects

Provides

few or no

benefits

Likely to

provide some

modest benefits

Potential for

significant

benefits, but

not well

understood

Provides

extensive,

quantifiable

benefits

44

Table 8. Task 1 - Scoring of Each Technology Option

Technology Option Energy

Savings

Fit with

DOE

Cost /

Complexity

Non-Energy

Benefits

Weighted

Score

Dishwashers

1. Advanced controls and sensors 1 5 4 3 3.2

2. Supercritical carbon dioxide washing 1 4 1 2 2.2

3. Ultrasonic washing 1 4 3 1 2.4

Cooktops

1. Catalytic burners (gas only) 1 4 3 2 2.5

2. Pulse combustion (gas only) 1 3 3 2 2.2

3. Radiant gas burners (gas only) 1 3 3 1 2.0

4. Reduced excess air at burner (gas only) 1 3 2 1 1.9

5. Specialized cookware (gas only) 1 4 3 3 2.7

Conventional Ovens

1. Bi-radiant oven (electric only) 2 3 4 1 2.5

2. Steam cooking (electric only) 1 2 3 3 2.0

Clothes Washers

1. Ionization 5 3 1 4 3.6

2. Plastic particle cleaning 4 4 1 4 3.6

3. Ultraviolet laundering 5 3 1 4 3.6

Clothes Dryers

1. Heat pump (electric only) 3 4 3 2 3.2

2. Indirect (hydronic) heating (electric only) 2 4 2 3 2.9

3. Inlet air preheating 2 4 4 2 3.0

4. Mechanical steam compression (electric only) 3 5 2 3 3.6

5. Microwave (electric only) 2 5 3 1 3.1

Refrigerators/Freezers

1. Improved compressor efficiency 2 3 4 2 2.7

2. Magnetic refrigeration 3 5 3 2 3.6

3. Nanoparticle additives to refrigerants 2 5 4 2 3.4

4. Stirling cycle 2 4 3 2 2.9

5. Thermoacoustic refrigeration 2 4 3 2 2.9

6. Thermoelectric refrigeration 3 4 4 2 3.4

7. Vacuum insulation panels 2 5 4 2 3.4

Cross-Cutting Technologies

1. Integrated energy and water recovery and

transfer between appliances 5 4 1 2 3.6

45

Table 9. Task 2 – Summary of R&D Needs and Key Risks

Appliance Technology Option Technology

Readiness Level R&D Needs Key Risks

Tier 1

1. Clothes Washers Plastic particle cleaning TRL 5 –

Laboratory Prototype

• First working prototypes to be built by Xeros

• Partnerships needed to test first operational prototypes

• Prototype testing in operational environment

• Prototype testing to confirm cleaning capabilities using AHAM test methods

• Cleaning ability of technology not yet proven to AHAM standards

• Uncertain consumer acceptance of new plastic particle technology

• Logistics of requiring period replacement of plastic beads

• Ability of technology to accommodate large U.S. laundry load sizes

2. Cross-Cutting

Integrated energy and

water recovery and

transfer between

appliances

TRL 5 –


• Laboratory tests of ZEHcore concept

• Measure and validate energy savings potential

• Additional tests simulating real-world usage patterns

• Pilot demonstration in a residential setting

• Would require total redesign of typical kitchen appliance layouts

• Feasibility not yet proven for energy/water recover and transfer concepts


• Would likely require changes to manufacturing processes


• Marketing changes required to shift away from single-appliance focus

3. Clothes Dryers

Mechanical steam

compression (Electric

only)

TRL 4 –

System Proof of

Concept

• Development of operational prototype

• Prototype testing of complete system under lab conditions

• Technology not yet proven in integrated system-level prototype

• Increased manufacturing cost compared to traditional dryers

• Uncertain consumer willingness to pay higher upfront cost

4. Refrigerator/Freezers Magnetic refrigeration

TRL 4 –

System Proof of

Concept

• Reduce size of technology

• Create integrated prototype for laboratory testing

• Create working prototype for field testing

• Concept is proven, but there is a low degree of certainty that the technology is feasible in a

residential setting

• Magnetic field of prototype was too high for use in residential homes

5. Refrigerator/Freezers Nanoparticle additives

TRL 4 –

System Proof of

Concept

• Develop prototype refrigerator with nanoparticle additives in laboratory conditions

• Acquire energy data from fully functional system

• Has not been tested in fully integrated system

• Uncertain energy saving benefits for residential refrigerators

6. Refrigerator/Freezers Vacuum insulation

panels

TRL 5 –


• Develop prototype for field testing to prove energy savings in residential environment

• Improve long-term integrity of insulation properties

• Reduce manufacturing costs

• Requires different manufacturing methods

• Low degree of certainty on longevity of VIPs


7. Refrigerator/Freezers Thermoelectric

TRL 4 –

System Proof of

Concept

• Demonstrate energy savings potential of thermoelectric technology

• Develop prototypes for lab testing

• Develop prototype for operational testing

• Unproven energy savings compared to vapor-compression refrigeration (small-scale models on the

market show low energy efficiency)

• Requires different manufacturing methods

• Uncertainty regarding ability to scale up manufacturing process

8. Clothes Dryers Heat pump (Electric

only)

TRL 8 –

Commercial

Demonstration

• Revival of previous prototypes

• Additional design and development

• Additional laboratory testing

• Pilot testing of redesigned prototype

• Technology not yet proven for large U.S. laundry load sizes



Tier 2

1. Clothes Washers Ionization TRL 2 –

Applied R&D

• Evaluation of negative ion technology as a method for laundering typical clothing

• Proof of concept demonstration to show technology viability

• Investigate feasibility of laundering more than one garment at a time with this

technology

• Unproven feasibility of technology to adequately clean clothes



• Significantly different manufacturing processes required

• Increased manufacturing cost compared to traditional clothes washers

• Uncertain consumer acceptance of new ionization technology

2. Clothes Washers Ultraviolet laundering TRL 2 –

Applied R&D

• Evaluation of ultraviolet + "free radical oxygen" technology as a method for laundering

typical clothing


• Investigate feasibility of laundering more than one garment at a time with this

technology

• Unproven feasibility of technology to adequately clean clothes





• Uncertain consumer acceptance of new ultraviolet laundering technology

3. Dishwashers Advanced cleaning

sensors

TRL 2 –

Applied R&D

• Identification of possible sensors that could be used

• Evaluation of existing sensor technologies in other products

• Proof of concept laboratory designs

• Unproven feasibility of new sensor technologies

• Unproven energy/water savings potential

• Increased manufacturing cost compared to traditional dishwasher sensors

46



4. Clothes Dryers Microwave (Electric

only)

TRL 7 –

Operational System

Pilot

• Reduction of upfront costs

• Refinements to improve energy efficiency

• Partnership with reputable brand name



• Uncertain consumer acceptance of microwave dryer technology

• Potential safety issues

5. Clothes Dryers Inlet air preheat

TRL 4 –

System Proof of

Concept • Lab testing of technology integrated into residential-style dryer




• Potential impacts on installation procedures

• Potential safety issues with lint handling

6. Refrigerator/Freezers Thermoacoustic

TRL 3 –

Component Proof of

Concept

• Package components to fit within refrigerator dimensions

• Development of fully integrated system for lab testing


• Very early stages of development with very rudimentary laboratory prototypes

• Low degree of certainty that technology is feasible


7. Refrigerator/Freezers Stirling cycle TRL 5 –


• Design refinements to improve energy efficiency

• Validation of energy savings potential



• May require different manufacturing methods

8. Clothes Dryers Indirect heating

TRL 9 –

Full Commercial

Deployment • Acquire energy efficiency data from current products on the market




9. Refrigerator/Freezers Improved compressor

efficiency

TRL 6 – Operational

Prototype

• Further develop technology to determine commercial feasibility

• Acquire additional performance data

• Incorporation into commercial designs

• Patent protection could diminish competition in the market

• Limited performance data on high-efficiency compressors

10. Cooktops Specialized cookware

TRL 7 –

Operational Pilot

System

• Investigate consumer acceptance

• Develop programs to increase consumer awareness and acceptance

• Unsure if cookware will be accepted by consumers

• Unproven energy savings in real world

Tier 3

1. Ovens Bi-radiant oven (Electric

only)

TRL 5 –


• Address practicality concerns

• Develop prototype for field testing

• Technical and feasibility issues arose with 1970s prototypes

• Low degree of certainty that technology is feasible with modern cookware

• Durable lining materials may add costs to consumers

2. Cooktops Catalytic burners (Gas

only)

TRL 4 –

System Proof of

Concept

• Integrate technology into fully functional prototype for lab testing

• Develop prototype for operational field testing

• Technical hurdles still remain

• Different manufacturing methods required

• High production costs


3. Dishwashers Ultrasonic washing

TRL 4 –

System Proof of

Concept

• Evaluation of current Indian product

• Evaluation of suitability for translating technology to U.S. residential needs

• Development of residential-style functioning prototype

• Unproven feasibility of technology to adequately clean dishes


• Ability of technology to accommodate U.S. residential dish loads



• Uncertain consumer acceptance of new ultrasonic technology

4. Dishwashers Supercritical carbon

dioxide washing

TRL 2 –

Applied R&D

• Evaluation of CO2 dishwashing technology as a method for cleaning household dishes


• Investigate feasibility of packaging into residential-size unit

• Unproven feasibility of technology to adequately clean dishes


• Ability of technology to accommodate U.S. residential dish loads



• Uncertain consumer acceptance of technology

5. Cooktops Pulse combustion (Gas

only)

TRL 5 –

Laboratory Prototype • Develop prototype for field testing



6. Cooktops Radiant gas burners (Gas

only)

TRL 5 –

Laboratory Prototype • Develop prototype for field testing


• Unproven energy savings in real world

7. Ovens Steam cooking

TRL 9 –

Full Commercial

Deployment • Acquire energy efficiency data from current products on the market

• Unsure of consumer acceptance

• No energy efficiency data available

• Some models require plumbing lines to supply water

47



8. Cooktops Reduced excess air at

burner (Gas only)

TRL 3 –

Component Proof of

Concept

• Determine energy savings potential of this technology

• Integrate components into full scale prototype for lab testing

• Low degree of certainty that technology is feasible


• No prototypes exist

48

Table 10. Task 3 - Summary of R&D Objectives, Tasks, Possible Performers, and Resources Required

Appliance

Technology

Option R&D Objective Outcomes of Achieving Objective a

R&D Tasks Possible Performers & Roles Duration & Resources Required

Tier 1

1. Clothes

Washers

Plastic particle

cleaning

To assess the energy savings

potential and cleaning performance

by procuring a working prototype

and performing tests using the DOE

test procedure (adapted if necessary)

and AHAM test procedures.

• Reliable estimates of energy savings

potential

• Procure a working prototype unit

• Perform testing using an adapted version of

the DOE test procedure

• Perform cleaning performance testing using

AHAM test procedures

• Estimate unit energy savings potential

based on results

• Xeros, Ltd: manufacturer of prototype,

cooperation with DOE project

• BTP: provide funding, manage test program,

develop test protocols

• National laboratory: perform energy &

performance tests

• DOE Standards & Test Procedure team:

provide background/insights, help evaluate

test results

Duration: 1 year

• Procurement of a prototype unit

• BTP project staff to manage test program

• National laboratory staff for testing

• DOE Standards & Test Procedure staff to help analyze

results

2. Cross-Cutting

Integrated energy

and water

recovery &

transfer between

appliances

To measure and validate the energy

savings potential of the ZEHcore

concept by performing laboratory

tests simulating real-world usage

patterns, and through a pilot



• Validation of integrated appliances

concept

• Preliminary estimates of energy savings

potential

• Feedback and experience from pilot

installation

• Develop fully integrated prototype system



• Perform preliminary laboratory testing

using actual appliances





• Conduct further laboratory tests simulating

real-world usage patterns

• Conduct pilot demonstration in a residential

setting


manage pilot program

• ORNL: development and refinement of

ZEHcore system


conditions

Duration: Multi-year


• Materials & supplies for further system development

• Test equipment & materials required for testing (including

appliances)

• Funding and program support for small-scale pilot testing

3. Clothes

Dryers

Mechanical steam

compression

(electric only)

To validate the technology concept

by developing a working prototype

and performing testing under


• Fully functional prototype that could be

further tested


potential




• Perform preliminary testing using clothing

loads





• BTP: provide funding, monitor progress

• Center for Energy Studies, Ecole des Mines

de Paris (Mines ParisTech): expand on

previous research and prototypes

• U.S. university: joint research activities with

Center for Energy Studies

Duration: 1 year


• Materials & supplies for component development and

system integration

• Test equipment & materials required for testing

4. Refrigerator/F

reezers

Magnetic

refrigeration

To demonstrate the required cooling

capacity of residential refrigerators.

• Working prototype for further coefficient

of performance testing

• Validation of cooling performance of

magnetic refrigeration


cooling principles


system





• Ames Laboratory: expand on previous

research and prototype


• Materials & supplies for component development and

system integration

• Ames staff to test and analyze results

5. Refrigerator/F

reezers

Nanoparticle

additives

To confirm preliminary energy

savings estimates using a residential

refrigerator on the U.S. market and

the DOE test procedure.


potential

• Test optimum solution from previous

studies in a residential refrigerator using the

DOE test procedure

• Estimate energy savings potential from

laboratory test results



• Researchers involved with preliminary

prototypes: provide knowledge and experience

from development of initial prototypes

• third-party laboratory: perform energy tests

using DOE test procedure

Duration: 1 year

• Materials: refrigerants, nanoparticle additives

• Refrigerators in which to test the refrigerants

• NIST staff to test and analyze results


1 2 3 4 5 6 7 8 9

0 1 2

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0 1 2

49

Appliance

Technology



6. Refrigerator/F

reezers

Vacuum

insulation panels

To understand the causes of

inconsistent results among multiple

manufacturers’ products and to

reduce overall costs.

• Understanding of the technical reasons

for inconsistent performance across

products

• Understanding of the primary cost

drivers, and strategies for creating a more

cost-effective product







VIPs




perform supply chain analysis

• third-party laboratory: perform energy tests

using DOE test procedure, perform reverse-

engineering analysis

• Manufacturers: R&D partnership with

manufacturers who already produce VIPs


• Refrigerator products with VIPs


• ORNL staff to test and analyze results

7. Refrigerator/F

reezers Thermoelectric

To determine the potential energy

savings of a full-sized residential

thermoelectric refrigerator by


laboratory testing.

• Working prototype for further testing


potential








• Manufacturers: R&D partnership with

manufacturers who already produce small

thermoelectric refrigerators

• National laboratory: aide in R&D


• Small thermoelectric refrigerators to analyze

• Materials to build full-sized prototype

• Research staff to build, test, and analyze prototype

8. Clothes

Dryers

Heat pump

(electric only)

To support the development of

ENERGYSTAR criteria for heat

pump dryers.

• ENERGYSTAR certification for heat

pump dryers

• Collaborate with EPA and stakeholders to

develop ENERGYSTAR criteria for heat

pump dryers

• Perform energy testing and analysis to

support ENERGYSTAR program

• BTP: provide program support, manage test

program


• Funding for program staff


Tier 2

1. Clothes

Washers Ionization

To assess the viability of using

ionization cleaning technology in a

residential laundry setting.

• Validation of technology concept

• Development of key system components

• Preliminary estimates of potential energy

savings

• Verify development status of negative ion

technology for clothes laundering

• Develop individual components of the

system

• Demonstrate proof-of-concept of individual

components

• Investigate feasibility of technology as a

method for residential laundering

• Determine preliminary estimates of energy

savings potential


• Electrolux: provide information &

background on technology concept from

design competition

• National Laboratory: conduct R&D and

testing of individual components

Duration: 1 year


• Materials & supplies for component development


2. Clothes

Washers

Ultraviolet

laundering

To assess the viability of using

ultraviolet cleaning technology in a

residential laundry setting.


• Development of key system components

• Preliminary estimates of potential energy

savings

• Verify development status of ultraviolet

technology for clothes laundering

• Develop individual components of the

system

• Demonstrate proof-of-concept of individual

components

• Investigate feasibility of technology as a

method for residential laundering

• Determine preliminary estimates of energy

savings potential




design competition


testing of individual components

Duration: 1 year




3. Clothes

Dryers

Microwave

(electric only)

To demonstrate a safe microwave

dryer by developing a pre-

commercial demonstration unit.

• Development of a safe commercial-ready

dryer that would be feasible for the US

market


potential

• Refine previous prototype models to

address safety concerns

• Develop pre-commercial demonstration

unit

• Perform pilot testing in residential settings

• Perform testing using an adapted version of

the DOE test procedure

• Estimate unit energy savings potential

based on results


program


design improvements


conditions




• Test equipment & materials required for internal testing

1 2 3 4 5 6 7 8 9

0 1 2

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0 1 2

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0 1 2

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0 1 2

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0 1 2

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0 1 2

50

Appliance

Technology



4. Clothes

Dryers Inlet air preheat

To demonstrate a viable inlet air

preheating technology for

residential dryers.

• Demonstration of feasibility of heat

transfer technology for residential dryers


potential

• Perform testing to characterize energy

benefits of current "heat wheel" technology

• Demonstrate smaller-scale design that

could be applicable to residential dryers

• Develop modified residential dryer with air

inlets/outlets to work with heat wheel

technology

• Investigate the potential for installing heat

exchanger inside dryer cabinet


program


design improvements

• Rototherm company: provide samples of

current technology, cooperate with DOE

project

Duration: 1 year


• Materials & supplies for testing current system

• Materials & supplies for developing modified components

• Test equipment & materials required for internal testing

5. Refrigerator/F

reezers Thermoacoustic

To demonstrate a thermoacoustic

refrigerator with the same

coefficient of performance as

commercially available residential

refrigerators.


• Demonstrated feasibility for residential

refrigerator applications

• Preliminary model of energy savings

potential

• Refine previous prototype model to

improve coefficient of performance

• Test refined prototype to determine

performance



• Universities involved with proof of concept:

provide knowledge and experience from

development of initial prototype






• DOE Standards staff to help analyze results

6. Refrigerator/F

reezers Stirling cycle

To determine the energy savings

potential of stirling cycle

refrigerators by developing and

testing a working prototype.



potential








• Purdue University: provide knowledge and

expertise on stirling cycle small refrigeration

research


• Research staff to develop and test prototype


7. Clothes

Dryers Indirect heating


potential of indirect (hydronic)

clothes dryers by testing hydronic

clothes dryers currently available on

the market.

• Resolve outstanding questions raised

during DOE Standards rulemaking

• Verification of additional savings from

back-to-back laundry cycles


potential


• Perform testing using DOE test procedure

(adapted if necessary)


• Hydromatics Technologies: provide units for

testing



• Third-party accredited laboratory: perform

energy & performance tests


background/insights, help evaluate test results

Duration: 6 months




• DOE Standards staff to help analyze results

9. Cooktops Specialized

cookware

To verify energy savings potential

of residential-sized cookware, and

to determine consumer acceptance

of specialized cookware by

implementing a trial consumer

incentive program.

•Verification of energy savings in

residential-sized cookware using

residential cooking equipment

• Knowledge about consumer acceptance

of specialized cookware

• Procure residential-sized specialty

cookware

• Perform investigative energy testing to

verify energy efficiency potential

• Implement trial consumer incentive

program to stimulate purchases of

specialized cookware

• Determine consumer acceptance rate and

feasibility


develop test protocols, design and execute

consumer incentive program

• Third-party laboratory: perform energy tests

• Cookware manufacturers: assist in consumer

programs

Duration: 1 year


•Third-party laboratory for testing

• Staff to carry out consumer programs and analyze results

• Funds for incentive program

1 2 3 4 5 6 7 8 9

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0 1 2

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0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

51

Appliance

Technology



Tier 3

1. Cooktops Catalytic burners

(gas only)

To investigate the viability for use

in residential applications and to

determine the energy savings

potential of catalytic burner

technology.


applications

• Preliminary estimate of energy savings

potential

• Develop integrated bench-top prototype

• Test prototype to determine energy savings

potential



• Precision Combustion, Inc. : provide product

knowledge and expertise

Duration: 1 year

• Equipment and materials required to build prototype

• Research staff to build, test, and analyze prototype results

2. Dishwashers Ultrasonic

washing

To investigate the energy savings

potential, cleaning performance, and

overall viability of ultrasonic

technology in residential

dishwashers.


• Assessment of overall concept viability


potential

• Procure the model currently available on

the Indian market

• Perform exploratory testing to verify

cleaning performance, energy consumption,

sanitization, and safety.


• Steryl Medi-Equip Systems: provide

products from India, cooperate with DOE



• National Laboratory: perform exploratory

testing

Duration: 1 year

• Procurement of an Indian product for testing

• Research staff to manage test program

• Equipment & materials required for testing

3. Dishwashers

Supercritical

carbon dioxide

washing

To determine the technology’s

development status, assess its

cleaning performance, and assess

the viability of using supercritical

carbon dioxide technology in

residential dishwashers.

• Determination of technology

development status

• Assessment of cleaning performance •

Assessment of overall concept viability

• Verify development status of supercritical

CO2 dishwasher

• Demonstrate proof-of-concept of cleaning

performance in benchtop prototype

• Investigate feasibility of technology for

residential dishwashers




design competition

• National Laboratory: conduct feasibility

study, laboratory testing

Duration: 1 year

• Research staff for R&D

• Equipment & materials required for testing

4. Cooktops Pulse combustion

(gas only)

To validate the energy savings

potential of pulse combustion gas

burners.


applications

• Reliable estimate of energy savings

potential

• Procure/develop working prototype based

on patented technology


potential



• GRI: Provide knowledge and expertise

• National Laboratory: aide in testing

Duration: 1 year


• Research staff to build, test, and analyze prototype results


5. Cooktops Radiant gas

burners (gas only)

To validate the energy savings

potential of radiant gas burners.


applications

• Reliable estimate of energy savings

potential

• Procure previously developed prototypes


potential



• American Gas Association Laboratories:

provide product knowledge and expertise

• National Laboratory: aide in testing

Duration: 6 months

• Procurement of prototypes

• Research staff to test and analyze results


6. Ovens Steam cooking


potential of steam-cooking ovens

currently on the market.


potential


• Perform testing using adapted DOE test

procedure




• Third-party accredited laboratory: perform

energy tests

• Manufacturers: provide commercially

available steam-cooking ovens

Duration: 6 months

• Procurement of commercially available steam-cooking

ovens


• Research staff to test and analyze results

7. Cooktops

Reduced excess

air at burner (gas

only)

To confirm theoretical energy

savings potential by developing and


• Proof-of-concept of technology

• Working system for further testing and

development

• Preliminary estimate of energy savings

potential

• Replicate components from previous

studies

• Integrate components to create a prototype

cooktop system

• Test system for basic functionality




• Prior researchers: provide basic knowledge

and expertise

Duration: 1 year


• Research staff to build, test, and analyze prototype results a Black fill numbers indicate current TRL status, while grey fill numbers indicate target TRL status after achieving the overall R&D objective.

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

1 2 3 4 5 6 7 8 9

0 1 2

# : Current TRL status

# : Projected R&D status after TRL activities

52

Table 11. Task 4 - Refrigerator/Freezer Summary of Stakeholder Comments

Technology

Option R&D Objective R&D Tasks Discussion Summary

Consensus Priority

(Change Indicated)

Tier 1 (High Priority)

Magnetic

refrigeration

To demonstrate the required cooling capacity of


• Further understand magnetic refrigeration cooling principles

• Optimize individual components of the system

• Test optimized prototype to demonstrate required cooling capacity

A major challenge with this technology is achieving the required temperature lift to

obtain necessary cooling capacity

Further R&D needed to fully understand the magnetic cooling effect and to develop

methods for transferring heat away from the food compartments

Fundamentally, this technology holds strong promise as a future alternative to

vapor compression.

HIGH (no change)

Nanoparticle

additives

To confirm preliminary energy savings estimates

using a residential refrigerator on the U.S. market

and the DOE test procedure.

• Test optimum solution from previous studies in a residential refrigerator

using the DOE test procedure

• Estimate energy savings potential from laboratory test results

Nanoparticles may improve the evaporator side of the heat exchanger, but would

have little effect on the condensing side. This would limit the overall efficiency

gains

Overall, this technology unlikely to offer significant energy savings

REMOVED FROM

CONSIDERATION

Vacuum

insulation panels

To understand the causes of inconsistent results

among multiple manufacturers’ products and to

reduce overall costs.

• Perform characterization tests on products known to have inconsistent

performance

• Reverse-engineer products to determine root causes for performance

inconsistencies

• Analyze the supply chain of all materials and processes used in the

manufacture of VIPs

• Determine major cost drivers and identify strategies for reducing costs

VIPs currently used in a limited number of products

Key challenges include long-term performance degradation and manufacturing

cost

HIGH (no change)

Thermoelectric

To determine the potential energy savings of a

full-sized residential thermoelectric refrigerator

by developing prototypes for laboratory testing.



• Modify/optimize internal components based on preliminary testing


Concept is feasible, but may not have the potential to be as efficient as vapor

compression

Could potentially be used in a hybrid system with vapor compression

Useful R&D would investigate the breakthroughs required to make this

technology competitive with vapor compression

LOW (downgrade)


Thermoacoustic

To demonstrate a thermoacoustic refrigerator

with the same coefficient of performance as

commercially available residential refrigerators.

• Refine previous prototype model to improve coefficient of performance

• Test refined prototype to determine performance

Component size and vibration are significant barriers for commercialization

Technology not being actively pursued by major manufacturers

REMOVED FROM

CONSIDERATION

Stirling cycle

To determine the energy savings potential of

stirling cycle refrigerators by developing and






Stirling cycle technology well-known, but has not been shown to be more efficient

than vapor compression

Technology not being actively pursued by major manufacturers

LOW (downgrade)

More efficient

compressor

technologies

Not previously considered Not previously considered

Could be implemented in short-term with traditional vapor compression systems

Estimations show linear compressors are more efficient than current fixed speed

compressors

R&D needed to optimize advanced compressor design, material selection,

lubricants, and manufacturing costs

MEDIUM

Tier 3 (Low Priority)

Thermoelastic Not previously considered Not previously considered

Cooling can be obtained from the straining of a thermoelastic shape memory alloy

Has drawbacks in its current preliminary form such as low latent heat (~12 kJ/kg)

and a limited fatigue life

Researchers currently developing a 35kW prototype

LOW

53

Table 12. Task 4 - Clothes Washer Summary of Stakeholder Comments

Technology


Consensus Priority (Change

Indicated)


Plastic particle

cleaning

To assess the energy savings potential and

cleaning performance by procuring a working

prototype and performing tests using the DOE

test procedure (adapted if necessary) and AHAM

test procedures.

• Procure a working prototype unit

• Perform testing using an adapted version of the DOE test procedure

• Perform cleaning performance testing using AHAM test procedures

• Estimate unit energy savings potential based on results

Concerns persist regarding potential environmental and safety issues with small

plastic beads

Technology could be better suited for commercial on-premise laundries or dry-

cleaning settings

Energy savings potential may be less significant compared to the most efficient

front-loading clothes washers on the market

MEDIUM (downgrade)


Ionization

To assess the viability of using ionization

cleaning technology in a residential laundry

setting.

• Verify development status of negative ion technology for clothes

laundering

• Develop individual components of the system

• Demonstrate proof-of-concept of individual components

• Investigate feasibility of technology as a method for residential

laundering

• Determine preliminary estimates of energy savings potential

No cleaning mechanism has been identified with this technology

Unlikely to become a viable replacement for regular home laundering

Could be used as a supplement to sanitize clothes

REMOVED FROM

CONSIDERATION

Ultraviolet

laundering

To assess the viability of using ultraviolet

cleaning technology in a residential laundry

setting.

• Verify development status of ultraviolet technology for clothes

laundering

• Develop individual components of the system

• Demonstrate proof-of-concept of individual components

• Investigate feasibility of technology as a method for residential

laundering

• Determine preliminary estimates of energy savings potential

No cleaning mechanism has been identified with this technology

Unlikely to become a viable replacement for regular home laundering

Could be used as a supplement to sanitize clothes

REMOVED FROM

CONSIDERATION


Sanitizing agents Not previously considered Not previously considered

Sanitizing agents can be added to cold water to reduce the need for hot water

washing

R&D needed to investigate the safety & environmental effects of certain sanitizing

agents

LOW

54

Table 13. Task 4 - Clothes Dryer Summary of Stakeholder Comments

Technology


Consensus Priority

(Change Indicated)


Mechanical steam

compression

(electric only)

To validate the technology concept by developing

a working prototype and performing testing under



• Characterize system performance and compare to modeled predictions

• Perform preliminary testing using clothing loads


• Further refine design to produce fully functional prototype system

Technology seems feasible, but not likely to have greater energy savings potential

than heat pump dryers

Technology will require additional seals and pressurized compartments to

accommodate pressurized steam, which will increase cost and complexity over

standard heat pump design

MEDIUM (downgrade)

Heat pump

(electric only)

To support the development of ENERGYSTAR

criteria for heat pump dryers.

• Collaborate with EPA and stakeholders to develop ENERGYSTAR

criteria for heat pump dryers

• Perform energy testing and analysis to support ENERGYSTAR

program

General recognition of heat pump’s success in Europe

Expectation by industry that heat pump technology will enter the North American

market in the future

Technology would benefit from ENERGY STAR support, utility/government rebates,

and pilot testing upon introduction of first commercial units in the market

HIGH (no change)


Microwave

(electric only)

To demonstrate a safe microwave dryer by

developing a pre-commercial demonstration unit.

• Refine previous prototype models to address safety concerns

• Develop pre-commercial demonstration unit

• Perform pilot testing in residential settings

• Perform testing using an adapted version of the DOE test procedure

• Estimate unit energy savings potential based on results

Manufacturers generally aware of previous development efforts of this technology

Safety concerns remain the key barrier to commercialization

LOW (downgrade)

Inlet air preheat To demonstrate a viable inlet air preheating

technology for residential dryers.

• Perform testing to characterize energy benefits of current "heat wheel"

technology

• Demonstrate smaller-scale design that could be applicable to residential

dryers

• Develop modified residential dryer with air inlets/outlets to work with

heat wheel technology

• Investigate the potential for installing heat exchanger inside dryer

cabinet

Manufacturers expressed general interested in the idea

Water condensation would require extra plumbing and a drain

Uncertainties regarding potential efficiency gains

Could be more practical for commercial laundry settings

MEDIUM (no change)

Indirect heating

To assess the energy savings potential of indirect

(hydronic) clothes dryers by testing hydronic

clothes dryers currently available on the market.


• Perform testing using DOE test procedure (adapted if necessary)


Confirmation of uncertainty of potential energy savings of back-to-back dryer

cycles

Lack of a cool-down phase before the load comes to a rest could pose a safety

hazard

LOW (downgrade)

Table 14. Task 4 - Dishwasher Summary of Stakeholder Comments

Technology


Consensus Priority

(Change Indicated)


Ultrasonic

washing

To investigate the energy savings potential,

cleaning performance, and overall viability of

ultrasonic technology in residential dishwashers.

• Procure the model currently available on the Indian market

• Perform exploratory testing to verify cleaning performance, energy

consumption, sanitization, and safety.


Technology does not seem realistic in American markets

Concerns about amount of water required

Technology may not be as useful on plastic dishware

REMOVED FROM

CONSIDERATION

Supercritical

carbon dioxide

washing

To determine the technology’s development

status, assess its cleaning performance, and assess

the viability of using supercritical carbon dioxide

technology in residential dishwashers.

• Verify development status of supercritical CO2 dishwasher

• Demonstrate proof-of-concept of cleaning performance in benchtop

prototype

• Investigate feasibility of technology for residential dishwashers

Unlikely to be accepted by residential consumers due to the need for high-pressure

CO2

REMOVED FROM

CONSIDERATION

55

Table 15. Task 4 - Cooking Equipment Summary of Stakeholder Comments

Technology


Consensus Priority

(Change Indicated)


Specialized

cookware

To verify energy savings potential of residential-

sized cookware, and to determine consumer

acceptance of specialized cookware by

implementing a trial consumer incentive program.

• Procure residential-sized specialty cookware

• Perform investigative energy testing to verify energy efficiency

potential

• Implement trial consumer incentive program to stimulate purchases of

specialized cookware

• Determine consumer acceptance rate and feasibility

Manufacturers expressed generally interest with the proposal

Technology could be more applicable in commercial settings MEDIUM (no change)

Induction cooking Not previously considered Not previously considered

Technology offers much higher efficiency than traditional electric or gas cooktops

Technology already available in the market

Technology not accommodated by current test procedure for cooking equipment

Technology could benefit from ENERGY STAR certification

MEDIUM


Catalytic burners

(gas only)

To investigate the viability for use in residential

applications and to determine the energy savings

potential of catalytic burner technology.

• Develop integrated bench-top prototype

• Test prototype to determine energy savings potential

Not likely to be embraced by manufacturers or consumers

Little to no energy savings

REMOVED FROM

CONSIDERATION

Pulse combustion

(gas only)

To validate the energy savings potential of pulse

combustion gas burners.

• Procure/develop working prototype based on patented technology




REMOVED FROM

CONSIDERATION

Radiant gas

burners (gas only)

To validate the energy savings potential of

radiant gas burners.

• Procure previously developed prototypes




REMOVED FROM

CONSIDERATION

Steam cooking To assess the energy savings potential of steam-

cooking ovens currently on the market.


• Perform testing using adapted DOE test procedure


Technology may be undesirable from consumer standpoint because consumers like

to get crispy sear on food, which steam does not provide LOW (no change)

Reduced excess

air at burner (gas

only)

To confirm theoretical energy savings potential

by developing and testing a working prototype.

• Replicate components from previous studies

• Integrate components to create a prototype cooktop system

• Test system for basic functionality


Little to no energy savings REMOVED FROM

CONSIDERATION

Oven coatings Not previously considered Not previously considered

Coatings with innovative materials could reduce the heat required

during self-clean cycles

Self-clean temperature could potentially be reduced by a few hundred

degrees

LOW

Smart burners Not previously considered Not previously considered

Technology would adjust flame to keep pot at constant temperature,

thus eliminating excess waste heat

Technology likely to be embraced by both manufacturers and

consumers

LOW

Table 16. Task 4 - Cross-cutting Summary of Stakeholder Comments

Technology


Consensus Priority (Change

Indicated)


Integrated energy

and water

recovery &

transfer between

appliances

To measure and validate the energy savings

potential of the ZEHcore concept by performing

laboratory tests simulating real-world usage

patterns, and through a pilot demonstration

project in a residential setting.


• Characterize system performance and compare to modeled predictions

• Perform preliminary laboratory testing using actual appliances


• Further refine design to produce fully functional prototype system

• Conduct further laboratory tests simulating real-world usage patterns

• Conduct pilot demonstration in a residential setting

Manufacturers expressed general interest in integrated energy and water recovery

and transfer between appliances

R&D efforts could focus on highly-insulated flexible tubing between appliances

Technology may be easier to implement in traditionally paired appliances (e.g.

washer and dryer)

HIGH (no change)

56

Appendix B Technology Readiness Level (TRL) System

This Appendix provides a description of the Technology Readiness Level (TRL) system referenced throughout

the report.

Table 17. Technology Readiness Level (TRL) System for Categorizing Technology Development Status

Relative Level of

Technology

Development

Technology

Readiness

Level (TRL) TRL Definition Description

Basic Technology

Research

TRL 1

Basic principles

observed and

reported

This is the lowest level of technology readiness. Scientific

research begins to be translated into applied R&D. Examples

might include paper studies of a technology’s basic properties

or experimental work that consists mainly of observations of

the physical world. Supporting information includes

published research or other references that identify the

principles that underlie the technology.

TRL 2

Technology concept

and/or application

formulated

Once basic principles are observed, practical applications can

be invented. Applications are speculative, and there may be

no proof or detailed analysis to support the assumptions.

Examples are still limited to analytic studies.

Research to

Prove Feasibility TRL 3

Analytical and

experimental critical

function and/or

characteristic proof

of concept.

Active research and development (R&D) is initiated. This

includes analytical studies and laboratory-scale studies to

physically validate the analytical predictions of separate

elements of the technology. Examples include components

that are not yet integrated or representative tested with

simulants. Supporting information includes results of

laboratory tests performed to measure parameters of interest

and comparison to analytical predictions for critical

subsystems. At TRL 3 the work has moved beyond the paper

phase to experimental work that verifies that the concept

works as expected on simulants. Components of the

technology are validated, but there is no attempt to integrate

the components into a complete system. Modeling and

simulation may be used to complement physical experiments.

Technology

Development TRL 4

Component and/or

subsystem validation

in laboratory

environment

The basic technological components are integrated to

establish that the pieces will work together. This is relatively

"low fidelity" compared with the eventual system. Examples

include integration of ad hoc hardware in a laboratory and

testing with a range of simulants and small scale tests.

Supporting information includes the results of the integrated

experiments and estimates of how the experimental

components and experimental test results differ from the

expected system performance goals. TRL 4-6 represent the

bridge from scientific research to engineering. TRL 4 is the

first step in determining whether the individual components

will work together as a system. The laboratory system will

probably be a mix of on-hand equipment and a few special-

purpose components that may require special handling,

calibration, or alignment to get them to function.

57

TRL 5

Laboratory scale,

similar system

validation in relevant

environment

The basic technological components are integrated so that the

system configuration is similar to (matches) the final

application in almost all respects. Examples include testing a

high-fidelity, laboratory scale system in a simulated

environment. Supporting information includes results from

the laboratory scale testing, analysis of the differences

between the laboratory and eventual operating

system/environment, and analysis of what the experimental

results mean for the eventual operating system/environment.

The major difference between TRL 4 and TRL 5 is the

increase in the fidelity of the system and environment to the

actual application. The system tested is almost prototypical.

Technology

Demonstration

TRL 6

Engineering/ pilot-

scale, similar

(prototypical) system

validation in relevant

environment

Engineering-scale models or prototypes are tested in a

relevant environment. This represents a major step up in a

technology’s demonstrated readiness. Examples include

testing an engineering scale prototypical system with a range

of simulants. Supporting information includes results from

the engineering scale testing and analysis of the differences

between the engineering scale, prototypical

system/environment, and analysis of what the experimental

results mean for the eventual operating system/environment.

TRL 6 begins true engineering development of the

technology as an operational system. The major difference

between TRL 5 and TRL 6 is the step up from laboratory

scale to engineering scale and the determination of scaling

factors that will enable design of the operating system. The

prototype should be capable of performing all the functions

that will be required of the operational system. The operating

environment for the testing should closely represent the

actual operating environment.

System

Commissioning

TRL 7

Full-scale, similar

(prototypical) system

demonstrated in

relevant environment

This represents a major step up from TRL 6, requiring

demonstration of an actual system prototype in a relevant

environment. Examples include testing full-scale prototype in

the field with a range of simulants. Supporting information

includes results from the full-scale testing and analysis of the

differences between the test environment, and analysis of

what the experimental results mean for the eventual operating

system/environment. Final design is virtually complete.

TRL 8

Actual system

completed and

qualified through test

and demonstration

The technology has been proven to work in its final form and

under expected conditions. In almost all cases, this TRL

represents the end of true system development. Examples

include developmental testing and evaluation of the system in

a realistic environment. Supporting information includes

operational procedures that are virtually complete.

System

Operations TRL 9

Actual system

operated over the full

range of expected

conditions

The technology is in its final form and operated under the full

range of operating conditions. Examples include using the

actual system with the full range of functionality.

Source: U.S. Department of Energy Technology Readiness Assessment Guide. Publication DOE G 413.3-4. October 12, 2009. (DOE, 2009)

58

Appendix C Description of Appliance Technology Options

This appendix provides detailed descriptions of each technology option, including current

development status and links to relevant source information. The order of technology

descriptions corresponds to the order in which the technologies are presented in the final report

above.

C.1 Refrigerator/Freezers

C.1.1 Magnetic Refrigeration

Magnetic refrigeration is based on the magneto-caloric effect (MCE). MCE is a magneto-

thermodynamic phenomenon in which a reversible change in temperature of a paramagnetic

material is caused by exposing it to a changing magnetic field. In the magnetic refrigeration

cycle, randomly oriented magnetic spins in a paramagnetic material are aligned via a magnetic

field, resulting in a rise in temperature. This heat is removed from the material to ambient by

means of heat transfer. Upon removal of the magnetic field, the magnetic spins return to its

randomized state thus cooling the material to below ambient temperature. The material is then

used to absorb heat from the refrigerated volume thus cooling that space and returning the

paramagnetic material to its original state and the cycle starts again. For room temperature

applications, materials are needed that have a Curie temperature (the temperature above which

ferromagnetic materials loss their permanent magnetism) around 295 K. Gadolinium and

Gadolinium alloys have a large MCE around this temperature range and they are among the

most widely used materials for room temperature refrigeration and space cooling applications.

A working prototype has been developed at

the Ames Laboratory. However, due to the

high magnetic field, the system is not

applicable for use at home. The ultimate

goal of this research would be to develop a

standard refrigerator for home use.

Sources:

1. United States Department of Energy.

Final Rule Technical Support Document: Refrigerators, Refrigerator-Freezers, and Freezers.

August 25, 2011. Available online at

http://www1.eere.energy.gov/buildings/appliance_standards/pdfs/refrig_finalrule_tsd.pdf

2. Idea Connection, July 2010. http://www.ideaconnection.com/new-inventions/magnetic-

refrigeration-03730.html


http://www.ideaconnection.com/new-inventions/magnetic-refrigeration-03730.html

http://www.ideaconnection.com/new-inventions/magnetic-refrigeration-03730.html

59

C.1.2 Vacuum Insulation Panels

Vacuum-insulated panel (VIP) technology is based on the reduction in conductivity that occurs

in a low vacuum. VIPs used in refrigeration products consist of a sealed package with a fill

material which provides support to prevent the panel from collapsing and interferes with

molecular mean free path as the intermolecular spacing increases at lower vacuum levels. VIPs

can be foamed in place between the cabinet liner and wrapper to decrease the heat leakage and

energy required to maintain the cabinet at low temperature. Different configurations are

commercially available through advances in manufacturing technologies. As a result, VIPs are

available in a variety of geometries (e.g., flat, curved, cylindrical) with added features (e.g.,

holes, cut-outs). Typical VIPs generally consist of a core material and an airtight envelope.

Some VIPs also include absorber to absorb gas which leaks through the envelope.

Of significant concern for VIPs is their long-term thermal conductivity integrity. VIP thermal

conductivity increases dramatically as the pressure within the VIP exceeds 100 Pa (1 mbar). The

pressure increase in the VIP over time is related to several factors, including: residual gases in

the VIP after vacuum, degassing from the VIP core material, and gas diffusion through the

envelope pores. Improved envelopes and absorbers have been developed to prevent pressure

increases from occurring in VIPs. Oak Ridge National Laboratory (ORNL) analyzed three

composite VIPs and measured only a five-percent reduction in overall thermal resistance over a

three-year period. ORNL demonstrated that this reduction in thermal resistance was less than

the corresponding reduction for a panel without any VIPs, i.e., panels consisting only of PU

foam insulation.

VIPs are currently commercially available, but research is ongoing in reducing the cost and

longevity of VIPs. Several core materials have been used in the manufacture of VIPs including

polystyrene, open-cell PU, silica powder, and glass fiber. Research sponsored by the European

Commission has evaluated these core materials based on their cost and characteristics,

including density and manufacturing time. Additionally, ORNL also has evaluated the

performance of three types of VIPs: a silica powder filler encapsulated in a polymer barrier film;

a fibrous glass insulation filler encapsulated in a stainless steel barrier; and an undisclosed

insulation filler encapsulated in a stainless steel barrier.

Source:

United States Department of Energy. Final Rule Technical Support Document: Refrigerators,

Refrigerator-Freezers, and Freezers. August 25, 2011. Available online at



60

C.1.3 Improved Linear Compressors

Linear compressors employ a different design than either reciprocating or rotary compressors

and are reportedly more efficient than both. These compressors use a linear rather than rotary

motor, thus eliminating the crankshaft and linkage which converts the rotary motion to the linear

motion of the piston of a reciprocating compressor. Elimination of the mechanical linkage

reduces friction and side-forces. The linear motor requires power electronics and a controller to

assure proper piston throw. Most linear compressor designs use a free piston arrangement and

can be controlled for a range of capacities through adjustment of piston displacement. Early

work on the concept suggested that the compressors can operate without requiring oil, which

could provide additional energy benefit by improving heat transfer in the evaporator.

Refrigerator noise levels can also be reduced by utilizing linear compressors in the same way

that this can be done with variable-speed compressors, by operating most of the time at low

capacity. Linear compressor may be about 9% more efficient than the best current-technology

rotating-shaft reciprocating compressors.

At least one manufacturer, LG, uses linear compressors in some of its commercially available

refrigerator/freezers. LG claims that the linear compressors emit lower noise levels and require

less energy to operate than conventional compressors.

Sources:

1. United States Department of Energy. Final Rule Technical Support Document: Refrigerators,



2. LG product website: http://www.lg.com/us/kitchen/refrigerator/energy-efficient-

refrigerator.jsp

Accessed March 21, 2012.

C.1.4 Stirling Cycle Refrigeration

A Stirling-cycle machine is a device that operates on a closed regenerative thermodynamic

cycle, with cyclic compression and expansion of the working fluid at different temperature

levels, and where the flow is controlled by volume changes, so that there is a net conversion of

heat to work or vice versa. “Regenerative” refers to the use of an internal heat exchanger, the

regenerator, which is an essential part of the Stirling cycle. A Stirling refrigeration cycle

compresses and expands an inert gas in a single cylinder. Heat is rejected at one end of the

cylinder and absorbed at the opposite end. In the absence of all thermodynamic losses, the

efficiency could be higher than for vapor compression systems. Various technical difficulties

have so far limited the use of Stirling-cycle cooling to small prototype domestic refrigerators.

There is no circulating refrigerant fluid and the hot and cold heat areas are relatively small,

which creates heat exchange challenges for any but the lowest-capacity systems.

Source: United States Department of Energy. Final Rule Technical Support Document:

Refrigerators, Refrigerator-Freezers, and Freezers. August 25, 2011. Available online at



http://www.lg.com/us/kitchen/refrigerator/energy-efficient-refrigerator.jsp

http://www.lg.com/us/kitchen/refrigerator/energy-efficient-refrigerator.jsp


61

C.1.5 Thermoelastic Refrigeration

Thermoelastic cooling is based on a thermoelastic shape memory alloy (SMA) that releases heat

when compressed and returns to its original shape when heated. Two or three alloys are

combined in precise proportions that permit them to take on two different internal structures,

depending on their temperature and pressure. Thermoelastic cooling occurs when an SMA is

strained or stretched, resulting in a solid phase change of the material. This phase change is

accompanied by a nearly-reversible temperature rise in the material. The material rejects heat to

its surroundings in its strained state. When the SMA is relaxed from its strained state, a solid

phase change occurs back to its initial phase. This phase change is accompanied by a nearly-

reversible temperature drop. In the relaxed state, the SMA absorbs heat from a temperature

source.

The efficiency of the thermoelastic cooling process is high, with a coefficient of performance

(COP) estimated at 11.8, which is double that of state-of-the-art vapor compression technology.

This technology, however, has drawbacks in its current preliminary form; these include a

relatively low latent heat (~12 kJ/kg) and a limited fatigue life. The University of Maryland,

collaborating with General Electric Global Research and the Pacific Northwest National

Laboratory, is developing a 0.01-ton prototype with the goal of establishing the commercial

viability of thermoelastic cooling.

Sources:

1. Quick, Darren. “'Thermally-elastic' metal to cut summer CO2 emissions and electricity

bills”. Gizmag July, 2010. http://www.gizmag.com/thermally-elastic-smart-metal/15793/

2. Thermoelastic Cooling”. Degrees.

http://www.reece.com.au/degrees/2011/Apr/thermoelastic.html

3. Smart Metals for Solid-State Cooling Nix Greenhouse Gases”. Smarter Technology.

http://www.smartertechnology.com/c/a/Technology-For-Change/Smart-Metals-for-

SolidState-Cooling-Nix-Greenhouse-Gases/

4. SBIR Phase I Award Abstract”. NSF.

http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1143093

5. Refrigeration Machines”. http://www.machine-history.com/Refrigeration%20Machines

6. New 'Smart' Metal Could Mean Cool Cash for Consumers, Less CO2”. July 15, 2010.

http://www.newsdesk.umd.edu/vibrant/release.cfm?ArticleID=2198

http://ge.geglobalresearch.com/

http://www.pnl.gov/

http://www.pnl.gov/

http://www.gizmag.com/thermally-elastic-smart-metal/15793/

http://www.reece.com.au/degrees/2011/Apr/thermoelastic.html

http://www.smartertechnology.com/c/a/Technology-For-Change/Smart-Metals-for-SolidState-Cooling-Nix-Greenhouse-Gases/

http://www.smartertechnology.com/c/a/Technology-For-Change/Smart-Metals-for-SolidState-Cooling-Nix-Greenhouse-Gases/

http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1143093

http://www.machine-history.com/Refrigeration%20Machines

http://www.newsdesk.umd.edu/vibrant/release.cfm?ArticleID=2198

http://www.gizmag.com/thermally-elastic-smart-metal/15793/picture/118092/

62

C.1.6 Thermoelectric Refrigeration

Thermoelectric cooling occurs when a current is passed across the junction of two dissimilar

metals. One side of the device becomes hot and the other becomes cold. Semiconductor

materials have relatively recently been developed that have allowed for the use of this type of

cooling in some applications. Thermoelectric cooling devices have no moving parts and have

extremely long lifetimes. There are several compact refrigerators and wine coolers using

thermoelectric cooling that are currently on the market, including several models offered by

Avanti Products. However, their efficiency is lower than traditional vapor-compression

models, and the technology is not yet suitable for standard-size residential refrigerator-freezers.

DOE tested a thermoelectric refrigerator from Haier, model HRT02WNC, a 1.7 cubic foot all-

refrigerator. Testing revealed that the thermoelectric module EER was 0.9 at a temperature lift

of at most 33 °F, an order of magnitude less than is achieved by conventional technology.

Sources:

1. United States Department of Energy. Final Rule Technical Support Document: Refrigerators,



2. Avanti Products, September 2011. http://www.avantiproducts.com/superconductor

C.2 Clothes Washers

C.2.1 Polymer Bead Cleaning

This technology is currently in development

by Xeros Ltd. in the United Kingdom.

Polymer bead cleaning uses the absorbent

properties of nylon polymer beads to clean

clothes. The nylon beads are added to the

wash drum with a small amount of water and

detergent to loosen the dirt or stains on the

clothing. The clothes are tumbled with the

polymer beads for around 45 minutes. The

polarity of the nylon polymer attracts stains

from the clothing. Under humid conditions,

the polymer becomes absorbent. Dirt is


http://www.avantiproducts.com/superconductor

63

attracted to the surface and then absorbed into the center of the bead. At the end of the cycle, the

polymer beads are separated from the clothing through an inner drum/outer drum rotation

process.

Research conducted in the United Kingdom has shown that this technology would reduce water

consumption by up to 90% compared to a traditional clothes washer. Including lower

temperature cleaning and reduced detergent consumption, total laundry carbon footprint would

be reduced by up to 40%.

According to the manufacturer’s website, Xeros Ltd. has successfully concluded two field trials

in the United Kingdom. One field study is in a commercial-scale dry cleaning setting and the

other is in a commercial-scale industrial setting. Additionally, development is ongoing to create

prototypes for residential use. The company is open to exploring R&D partnership

opportunities.

Source: Xerox, Ltd. March 2012. http://www.xerosltd.com/xeros-marketing.htm

C.2.2 Sanitizing Agents

Sanitizing agents, such as chemical or ionic compounds, can be added to the incoming cold

wash water to reduce the need for hot water washing. Clothes washers using such sanitizing

agents could offer cooler wash cycles that provide sanitization of the clothing; such wash cycles

typically require hot water temperatures up to 140°F.

One example of a sanitizing agent is the addition of silver ions to the cold wash water. Silver is

a natural disinfectant and can provide sanitization during a cold water wash. Samsung

previously offered silver ion injection as an alternative to the traditional hot water sanitization

cycle in its SilverCare™ line of front-loading residential clothes washers; however, clothes

washers with this feature are no longer available on the market. With this feature, silver is

electrolyzed during the wash and rinse cycles, and, according to Samsung, the released silver

ions penetrate into the fabric, killing bacteria and sanitizing the clothes. Samsung also states that

the silver ions eradicate bacteria and mold from inside the clothes washer, disinfecting the drum

and other internal parts.

http://www.xerosltd.com/xeros-marketing.htm

64

Because the silver ion injection feature can be used for sanitization in cold water, energy

savings can be achieved compared to a hot water or steam sanitization cycle. The sanitization of

the machine may also eliminate the need for period self-cleaning cycles commonly

recommended for front-loading clothes washers.

The long-term health effects of human and environmental exposure to nanoscale silver particles

are unknown. In September 2007, the U.S. Environmental Protection Agency (EPA) issued a

Federal Register notice in which it determined that clothes washers will be regulated as

pesticides if the machines contain silver or other substances, and if they generate ions of those

substances for express pesticidal purposes. According to this decision, a manufacturer would be

required to register a clothes washer with EPA as a pesticide if the product is marketed with

claims that it will kill bacteria on clothing.

In May 2008, a group of advocacy organizations sued the EPA asking the agency to issue new

rules regulating products containing nanoscale silver particles. The petition claimed that EPA

failed to adequately regulate products containing or using nanoscale silver particles. The petition

asks EPA to: (1) classify nanoscale silver as a new pesticide; (2) require detailed product

registration and data submissions under the Federal Insecticide Fungicide and Rodenticide Act;

and (3)analyze the potential environmental, health, and safety risks of nanoscale silver.

Sources:

1. United States Department of Energy. Draft Final Rule Technical Support Document:

Residential Clothes Washers. Draft copy March 21, 2012.

2. Samsung 2010. “Silver Nano Health System – Frequently Asked Questions.” Samsung

website. Accessed March 4, 2010.

http://ww2.samsung.co.za/silvernano/silvernano/wash_faq_popup.html

3. “Ions and Free Radicals.” Appliance Magazine, September 2007. Accessed online at

http://www.appliancemagazine.com/editorial.php?article=1820&zone=1&first=1

4. EPA Announcement. “Pesticide Registration: Clarification for Ion Generating Equipment.”

September 21, 2007. Accessed online at http://www.epa.gov/oppad001/ion_gen_equip.htm.

5. Monica, John C. “EPA Sued Over Nanoscale Silver.” Nanotechnology Law Report. May 3,

2008. Accessed online at http://www.nanolawreport.com/2008/05/articles/epa-sued-over-

nanoscale-silver.

C.3 Clothes Dryers

C.3.1 Heat Pump Clothes Dryer

Heat pump dryers function by recirculating the exhaust air back to the dryer while moisture is

removed by a refrigeration-dehumidification system. A heat pump dryer is essentially a dryer

and a dehumidifier packaged as one appliance. No heating element is needed. The warm and

damp exhaust air of the dryer enters the evaporation coil of the dehumidifier where it cools

down below the dew point, and sensible and latent heat are extracted. The heat is transferred to

the condenser coil by the refrigerant and reabsorbed by the air, which is moving in a closed air

cycle. A drain is required to remove the condensate; however, one is usually available since

clothes washers and dryers are typically located side by side.

http://ww2.samsung.co.za/silvernano/silvernano/wash_faq_popup.html

http://www.appliancemagazine.com/editorial.php?article=1820&zone=1&first=1

http://www.epa.gov/oppad001/ion_gen_equip.htm

http://www.nanolawreport.com/2008/05/articles/epa-sued-over-nanoscale-silver

http://www.nanolawreport.com/2008/05/articles/epa-sued-over-nanoscale-silver

65

Heat pump dryers have been unable to penetrate the U.S. market despite showing significant

energy savings. The major issue for heat pump dryers has been cost and performance. Heat

pump dryer cycle times are typically significantly longer than those associated with standard

U.S. electric dryers. More maintenance will probably be required for a heat pump dryer than for

a conventional dryer. The traditional heating element is replaced by equipment found in a small

room air conditioner— a condenser, evaporator, compressor, expansion valve, etc. Installation

costs, though, may be less than for a conventional electric dryer because the heat pump dryer

does not require an exhaust vent as does a conventional dryer (although some heat pump dryers

may still use a vent). However, heat pump dryers require access to a drain for removal of

condensate.

Research conducted on both heat pump dryers and conventional vented dryers on the European

market showed that heat pump dryers consumed about 50 percent less energy than conventional

dryers. The heat pump dryers tested had energy efficiency values between 0.32 and 0.40

kWh/kg laundry (with 70 percent initial moisture, measured according to test standard EN

61121) whereas conventional dryers had values between 0.6 and 0.8 kWh/kg laundry. Another

benefit noted by this research was that the leakage of water vapor into the room was around 20

percent, which is significantly lower than conventional dryers. This research performed a cost

comparison of heat pump dryers versus conventional dryers, which showed that the combined

sale price and electricity costs over 15 years was about 1900 and 2300 Euros, respectively.

According to the DOE technical support dryer for the clothes dryer energy conservation

standards, a heat pump dryer has been developed by a U.S. company which has successfully

tested several prototypes and found energy savings of 68 percent as compared to energy use by

a conventional electric clothes dryer. The estimated retail cost is approximately twice that of a

conventional electric dryer. Drying times were essentially the same as for the conventional

dryer, and the dryer operates on standard 120 V line power. The prototype uses a disposable

filter to reduce lint in the air system. One inch of polyisocyanurate insulation was used to avoid

condensation of water vapor in the recirculated air. In addition, the extension on the back of the

prototype dryer to accommodate the added refrigeration components was estimated to be about

the same depth as a vent duct, so the cabinet may fit in the same space as a conventional dryer.

Research sponsored by TIAX and Whirlpool developed a high efficiency, high-performance

heat pump clothes dryer for the U.S. market. This different approach to the heat pump system

maximized the output capacity and temperature from the heat pump. This design has shown 40

to 50 percent energy savings on large loads along with 35 degree Fahrenheit (°F) lower fabric

temperatures and similar drying times as conventional dryers. For delicate loads, the design

reduced fabric temperature by 10–30 °F and provide up to 50 percent energy savings and 30–40

percent drying time savings. The heat pump dryer designed by TIAX also exhibited improved

fabric temperature uniformity as well as robust performance across a range of vent restrictions

in a partially open-loop design.

66

In order to maximize the air inlet temperature

and airflow into the dryer’s drum, TIAX

replaced the standard refrigerant, R-22, with

R-134a in an R-22 air conditioner/heat pump

compressor, shifting evaporating and

condensing temperatures by 30 °F while

maintaining similar operating pressures and

power input. TIAX was also able to maximize

the capacity of the heat pump system by

redesigning the heat exchanger components to

optimize space utilization and increasing the

airflow in the system as compared to typical

dryers.

A key issue in the TIAX design was the

venting options of the heat pump dryer. The

moisture in the air exiting the drum is

removed by the evaporator. This air can then

be recirculated back into the drum, which removes the need for a vent. However, some form of

heat rejection is required since the heat pump generates more heat than cooling in steady state

operation. TIAX used a partially open-loop design in which a portion of the process air is vented

outdoors to remove excess heat. In this design, all of the process air is recirculated through the

dryer until the system has fully warmed, at which point the exhaust is opened and a portion of

the total flow is vented to the outside.

In the late 1980s, the Nyle Corporation developed a ventless heat pump dryer, funded through

a grant with the Department of Energy. The dryer reportedly used two-thirds less energy than a

traditional electric dryer and operated on a 110-volt circuit, rather than the typical 220-volts

required by traditional electric dryers. The estimated retail cost was approximately $800, around

twice the cost of a conventional dryer at the time. The dryer used a chlorofluorocarbon-based

refrigerant loop with a coefficient of performance of approximately 2.6. Drying times were

essentially the same as with a conventional dryer. The dryer used a disposable filter to reduce

the lint in the air system. Insulation was also used to avoid condensation of water vapor in the

recirculated air.

According to DOE dryer

rulemaking documents, the

prototypes were constructed by

modifying a conventional electric

dryer. The unit resembled a

conventional dryer except that it

contained the refrigerant system

in the rear of the cabinet, which

usually houses the electric heater.

The extension on the back of the

dryer was approximately the same

67

depth as a vent duct, so the cabinet could fit within the same space as a conventional dryer.

Nyle had arranged for an offshore manufacturer to make the heat pump dryers, but economic

problems that developed had prevented commercial units from being made.

Sources:

1. United States Department of Energy. Direct Final Rule Technical Support Document:

Residential Clothes Dryers and Room Air Conditioners. April 21, 2011. Available online at

http://www1.eere.energy.gov/buildings/appliance_standards/residential/residential_clothes_dry

ers_room_ac_direct_final_rule_tsd.html

2. E. Bush and J. Nipkow. 2006. Tests and Promotion of Energy-Efficient Heat Pump Dryers.

Report Prepared for International Energy Efficiency in Domestic Appliances & Lighting

Conference ’06.

3. P. Pescatore and P. Carbone. 2005. High Efficiency High Performance Clothes Dryer. Final

Report to Department of Energy.

4. V. Elaine Gilmore. November 1989. “Heat-pump clothes dryer.” Popular Science. pp.124-

126.

C.3.2 Inlet Air Pre-Heating

For this technology option, a heat exchanger is used to recover exhaust heat energy and to

preheat inlet air. This system should be feasible for both gas and electric dryers since none of

the exhaust air re-enters the dryer. Energy savings are achieved either by a faster drying time or

by reducing the required heater input power.

A limitation of this technology option is that a large surface area is required to achieve sufficient

heat transfer, and that lint may accumulate on these heat transfer surfaces. Although every dryer

is equipped with a lint filter, considerable lint is still contained in the exhaust air. This lint can

foul the heat exchanger, decreasing its effectiveness. Additionally, to overcome the increased

resistance to air flow, an extra blower is needed at the fresh air inlet or a stronger blower in the

exhaust air duct is required.

Manufacturers have also expressed concern that any decrease in exhaust temperature will lead to

moisture condensation in the exhaust duct, which could result in damage to the exhaust duct and

dryer, as well as water leakage into the home. Water leakage into the home could lead to the

health risks from the development of mildew and/or mold.

One example of a technology for recovering dryer exhaust heat is the Rototherm heat recovery

wheel, manufactured by Rototherm Corporation. Half of the heat recovery wheel is exposed

to the dryer air inlet, while the other half is exposed to the dryer exhaust inlet. The wheel is

constructed of alternate layers of flat and corrugated aluminum, as shown in the figure below.

http://www1.eere.energy.gov/buildings/appliance_standards/residential/residential_clothes_dryers_room_ac_direct_final_rule_tsd.html

http://www1.eere.energy.gov/buildings/appliance_standards/residential/residential_clothes_dryers_room_ac_direct_final_rule_tsd.html

68

As the heat wheel spins, heat is extracted from the exhaust outlet and transferred to the colder

dryer inlet air. A case study featured on the company website claims a fuel reduction of 44-51%

using the heat recovery wheel.

Source: Rototherm Corporation. http://www.rototherm.net/index1.html

C.3.3 Mechanical Steam Compression

The Center for Energy Studies has developed a super-heated steam (SHS) dryer using

mechanical steam compression (MSC). Instead of using hot air to dry the clothing, mechanical

steam compression dryers use water recovered from the clothing in the form of steam.

First, the tumbler and its contents are heated to the boiling point of water at 100°C/212°F. The

resulting wet steam purges the system of air, and the internal atmosphere is now pure water

vapor. As wet steam exits the tumbler, it is mechanically compressed to extract water vapor and

transfer the heat of vaporization to the remaining gaseous steam. The extracted water is drained

from the compression chamber, and the pressurized gaseous steam is allowed to expand and be

superheated before being injected back into the drum. Back in the drum, heat from the super-

heated steam causes more water to vaporize from the clothing, creating more wet steam and

restarting the cycle.

The considerably higher temperatures used in mechanical

steam compression dryers result in a one-hour drying time,

roughly half as long as the drying time for a heat pump

dryer. The energy consumption of a mechanical steam

compression dryer is roughly 55% less than a traditional

electric dryer.

The Center for Energy Studies has completed preliminary

performance testing on a compressor that could be used in

http://www.rototherm.net/index1.html

69

such a system. Computer simulations have been conducted to model the performance of a

complete working system; however, a working laboratory prototype has not yet been built.

Source: Palandre and Clodic. “Comparison of Heat Pump Dryer and Mechanical Steam

Compression Dryer” http://www-

cep.ensmp.fr/francais/innov/pdf/ICR0143SLV%20_IIR_IIF%20Conf.pdf

C.3.4 Indirect Heating (Hydronic) Clothes Dryer

For indirect heating, the clothes dryer heat energy is derived from an external heating system

such as the home’s hydronic heating system, or a stand-alone supplementary hydronic system.

This technology option uses a hydronic heating system to heat water which then flows through a

heat exchanger in the dryer, heating the air entering the drum. To use a home’s existing heating

system, significant plumbing would be required to circulate heated water through the heat

exchanger in the dryer. In its clothes dryer rulemaking, DOE was unaware of any data

quantifying potential energy efficiency improvements associated with indirect heating.

Hydromatics Technologies Corp. developed a built-in

hydronic heating system for electric dryers, marketed under

the Safe-Mates brand. In the system, a heat transfer fluids is

heated using an immersion element similar to a water heater.

The heated fluid passes through a heat exchanger, where the

heat is transferred to the air entering the drum, and is then

pumped back to the hydronic heater. The company claims that

their clothes dryer uses 50 percent less energy compared to a

conventional clothes dryer. However, it appears that this

estimate refers to the fact that the hydronic heating system

draws 2,500 Watts of power, versus a typical electric heater

that draws around 5,000 Watts. It is unclear whether the total

cumulative energy consumption over a complete cycle is less

than a conventional clothes dryer, because the cycle time for

the hydronic system may be longer. The website also claims

that because the system utilizes a proprietary heat transfer

fluid that retains its heat between loads much longer than a gas or electric clothes dryer's heating

system can, more energy can be saved when drying back-to-back loads. The Safe-Mates dryer is

also marketed as safer than a traditional electric dryer because of the reduced risk of lint fires.

Source: Hydromatic Technology Corporation. http://www.safe-mates.com/products.html

http://www-cep.ensmp.fr/francais/innov/pdf/ICR0143SLV%20_IIR_IIF%20Conf.pdf

http://www-cep.ensmp.fr/francais/innov/pdf/ICR0143SLV%20_IIR_IIF%20Conf.pdf

http://www.safe-mates.com/products.html

70

C.3.5 Microwave Clothes Dryer

Microwave energy can be absorbed by water, thereby heating the water enough to cause

evaporation. This would be a direct and efficient manner to remove moisture from clothes.

Instead of the conventional method of passing warm air over the clothes, microwave energy can

be directly absorbed by water retained in the clothing, thereby heating the water enough to cause

evaporation. Microwave drying uses the principle of dielectric heating, in which

electromagnetic energy is radiated into the dryer drum where it is absorbed by water molecules

which have a higher dielectric loss factor than most common fabric materials. Most fabric

materials are also relatively transparent to microwave energy, so that the microwaves can

penetrate the fabric’s interior to heat the water molecules directly. This allows the fabric in a

microwave dryer to stay cooler—below 115 °F—as compared to conventional dryers which heat

air to approximately 350 °F, with fabric surfaces reaching 150 °F.

Microwave dryer prototypes have been shown to consume about 17 to 25 percent less energy as

well as to dry clothes about 25 percent faster than conventional electric dryers.

Early conceptualization of this technology began in the mid-

1960s; however, product development was not pursued

because of high manufacturing costs and difficulties in

overcoming hazards relating to arcing and overheating of

clothing. In 1997, the Electric Power Research Institute

(EPRI) focused on developing a compact countertop dryer

based on economic feasibility and market surveys. EPRI

market studies and the development of prototypes for in-

house evaluation have led to negotiations for technology

licensing and indications of serious product development for

a residential microwave clothes dryer.

Because of the interaction between the metallic sensor contacts and the electromagnetic field,

microwave dryers are incapable of using contact moisture sensors as in conventional dryers.

EPRI investigated using sensors to detect the microwave electric field strength and the fabric

temperature, which both correlate well with the moisture content. As evaporation nears

completion, both measured signal slopes begin to rise in a predictable manner, so that the dryer

can be shut off automatically and avoid wasted energy in over-drying clothes.

Microwave drying also introduces a safety concern related to arcing. Arcing is caused by an

electric field which induces a voltage differential between metal objects, allowing current to

flow within them. The resultant heating and sparking of the metal objects may ignite a fire in the

load. EPRI has developed a rapid-response gas sensor to detect small amounts of gaseous by-

products of combustion in the exhaust stream. Upon detection, the drying cycle can be shut

down immediately, preventing safety hazards and damage. Another technique to avoid arcing is

to switch to electric resistance heaters when the clothes are almost dry.

Sources:

1. Ashley, Steven. 1998. “Energy-Efficient Appliances.” Mechanical Engineering. Vol. 120, No.

3, pp. 94–97.

71

2. J. Gerling. 2003. “Microwave Clothes Drying – Technical Solutions to Fundamental

Challenges.” Appliance Magazine. April 2003.

3. EPRI. “Microwave Drying of Textile Products.” October 1999.

http://my.epri.com/portal/server.pt?space=CommunityPage&cached=true&parentname=ObjM

gr&parentid=2&control=SetCommunity&CommunityID=404&RaiseDocID=00000000000100

6118&RaiseDocType=Abstract_id

C.4 Cooking Equipment

C.4.1 Induction Cooktops

Induction cooktops use a solid-state power supply to convert 60 hertz alternating line current

into a high-frequency (approximately 25 kilohertz) alternating current. This high-frequency

current is supplied to an inductor. The inductor is a flat spiral winding located underneath a

glass-ceramic panel. The high-frequency current, which is supplied to the inductor, causes it to

generate a magnetic field, which passes through the glass-ceramic panel unaffected and

produces eddy currents in the bottom of the cooking vessel. The vessel must be made of

ferromagnetic material, and the eddy currents that are generated within it cause it to heat up.

Thus, the vessel essentially becomes the heating element.

A sensor is placed between the inductor and the glass-ceramic panel, providing a continuous

temperature measurement of the vessel bottom. Sensors also enable the inductor to only heat

objects of at least 4 inches in diameter. This prevents any small metal objects, such as forks or

spoons, from accidentally being heated. In addition, since the glass-ceramic panel is unaffected

by the magnetic field, it remains relatively cool, reducing the potential for accidental burns.

The primary advantages of induction elements are their fast response and control of the heat

source, their ease of cleaning, and their ability to heat vessels that are not flat. Because these

features have usually been associated with gas burners, induction elements are being marketed

in competition to them.

As noted above, the cooking vessel used with an induction element must be made from a

ferromagnetic material. Since aluminum is not a ferromagnetic material, the current DOE test

procedure, which specifies an aluminum test block, cannot be used to rate this equipment. In

1978, the National Bureau of Standards (NBS), now called National Institute of Standards

and Technology (NIST), developed a proposed method of measuring the energy consumption

of induction cooktops. The method is a modification of the current DOE test procedure.

Energy use is determined by attaching a ferromagnetic material to the bottom of the aluminum

test block. This modification was never formally adopted by DOE.

Source:

United States Department of Energy. Final Rule Technical Support Document: Residential

Dishwashers, Dehumidifiers, Cooking Products, and Commercial Clothes Washers. Residential

Clothes Dryers and Room Air Conditioners. April 8, 2009. Available online at

http://www1.eere.energy.gov/buildings/appliance_standards/residential/cooking_products_final

_rule_tsd.html

http://my.epri.com/portal/server.pt?space=CommunityPage&cached=true&parentname=ObjMgr&parentid=2&control=SetCommunity&CommunityID=404&RaiseDocID=000000000001006118&RaiseDocType=Abstract_id



http://www1.eere.energy.gov/buildings/appliance_standards/residential/cooking_products_final_rule_tsd.html

http://www1.eere.energy.gov/buildings/appliance_standards/residential/cooking_products_final_rule_tsd.html

72

C.4.2 Specialized Cookware

Cookware modified with fins or grooves along the bottom surface have been shown to

significantly increase cooktop performance. Heat-up times are substantially reduced and

production capacities increased. Energy performance is also significantly improved. By simply

using an advanced pot design, the 25–30% energy efficiency of a standard, gas-fired range top

can be raised to more than 40%. When used on a range top with energy efficiency in the low

30s, the number can approach 60%.

Eneron Inc. has developed a line of cooking vessels that use aluminum fins to increase the

surface area exposed to the burner flame, thereby maximizing the amount of heat transferred to

the bottom of the pot.

Sources:

1. Appliance Magazine, August 2009.

http://www.appliancemagazine.com/ae/editorial.php?article=2257&zone=215&first=1

2. Eneron, Inc website: http://www.eneron.us/index.html Accessed march 21, 2012.

http://www.appliancemagazine.com/ae/editorial.php?article=2257&zone=215&first=1

73

C.4.3 Steam Cooking

With steam cooking, energy is transferred to the food load by means of the condensation of

steam on the food surface. This may take place at essentially atmospheric pressure, or the cavity

may be pressurized in order to allow higher steam temperatures and thus higher energy transfer

to the food. In order to maintain the proper environment regardless of pressure, a “steam-tight”

oven cavity must be maintained. In addition, the use of steam involves considerably higher

demands on the oven’s design and materials. Not only are different cavity materials required

(e.g., temperature-resistant silicone seals and chrome-nickel steel), but all incorporated elements

and accessories must be redesigned and intensively tested. Energy is saved because food items

that normally would need to be cooked separately (e.g., a meat roast in an oven and vegetables

on a cooktop) can be cooked together.

There are several electric ovens with steam

functions currently on the market. BSH Home

Appliances has recently introduced the Gaggenau

Combination Steam and Convection Oven. The

oven utilizes a steam injection valve to control

steam delivery to the cavity. The temperature and

humidity level in the oven are user-selectable to

tailor the cooking process as needed. Speed cooking

is not advertised as the primary feature of this oven.

Rather, food quality and nutrition is the focus. The

steam capability is described as allowing vegetables

to be cooked while retaining texture and nutritional

content, meat to be roasted without drying out, and

leftovers to be reheated without the loss of flavor

and texture often associated with microwave

reheating. Since this is a built-in oven, water delivery and condensate drainage are provided via

plumbing lines much like a dishwasher. Miele, Viking, and Gaggenau also market steam

convection ovens that do not require any external plumbing. Instead, they include a refillable

container for water supply and collection.

Sources:

1. Gaggenau, http://www.gaggenau.com/US_en/products/product-

detail.do?contentId=78b1160b-a568-4f52-8a4c-147fba99c97a

2. Miele

http://www.mieleusa.com/products/models_pages/3/19/models.html?nav=20&snav=110&tnav=

125&oT=38

3. Viking http://www.vikingrange.com/consumer/products/product.jsp?id=prod4840155

http://www.gaggenau.com/US_en/products/product-detail.do?contentId=78b1160b-a568-4f52-8a4c-147fba99c97a

http://www.gaggenau.com/US_en/products/product-detail.do?contentId=78b1160b-a568-4f52-8a4c-147fba99c97a

http://www.mieleusa.com/products/models_pages/3/19/models.html?nav=20&snav=110&tnav=125&oT=38

http://www.mieleusa.com/products/models_pages/3/19/models.html?nav=20&snav=110&tnav=125&oT=38

http://www.vikingrange.com/consumer/products/product.jsp?id=prod4840155

74

C.4.4 Advanced Oven Coatings

The self-cleaning cycle in ovens uses approximately 17% of the total annual energy

consumption (using four self-clean cycles per year). Innovative oven coatings could improve the

efficiency of the self-clean cycle by releasing food particles at lower temperatures. The reduced

self-clean temperatures will reduce the overall oven annual energy consumption.

Maytag recently introduced its “AquaLift” self-clean technology. This self-clean technology is

an interior oven that enables low heat and water to release baked-on spills in less than one hour.

Temperatures stay below 200 degrees as compared to ovens that require heat of up to 800

degrees during the self-cleaning cycle. In less than an hour, the oven is ready for a final wipe-

down to remove food and debris, with no odor or extreme heat like traditional high-temperature

self-clean ovens.

Sources:

1. Maytag, http://www.whirlpoolcorp.com/about/innovation/aqualift.aspx

2. Glaze, Ayana. “The Must-Have Self-Cleaning Oven of 2012”.

http://ext.homedepot.com/community/blog/the-must-have-self-cleaning-oven-of-2012/

http://www.whirlpoolcorp.com/about/innovation/aqualift.aspx

http://ext.homedepot.com/community/blog/the-must-have-self-cleaning-oven-of-2012/

http://ext.homedepot.com/community/blog/wp-content/wpuploads/Before_Aqualift.jpg

http://ext.homedepot.com/community/blog/wp-content/wpuploads/Aqualift_Pour.jpg

http://ext.homedepot.com/community/blog/wp-content/wpuploads/Aqualift_Wipe.jpg

http://ext.homedepot.com/community/blog/wp-content/wpuploads/After_Aqualift.jpg

75

C.5 Cross-Cutting Technologies

C.5.1 Integrated Heat & Water Recovery

Whirlpool has designed a prototype integrated kitchen design concept

where wasted water and heat are re-used from one appliance by another.

The system captures heat from the refrigerator's compressor and uses it

to pre-heat the dishwasher water. 60% of the water in the integrated

system is captured, undergoes anti-bacterial treatment and then stored in

an external water tank under the sink. This water can be used for the

dishwashing cycle. The refrigerator is compartmentalized into drawers

to prevent cold air from spill out when the doors are opened. Whirlpool

estimates that savings would result in 7 liters (1.8 gallons) of water per

cycle and up to 20% savings of electricity with the same washing

performance. In total, the concept claims to increased water and energy

efficiency by up to 70%.

Another concept, the Propane Energy Pod from the Propane Education & Research Council

(PERC), is intended to serve as a new energy model for homes. PERC describes it as a research-

based solution for home construction that treats five areas of energy use in a home: space

heating, water heating, cooking, clothes drying, and fireplaces, all as part of a whole-home

energy package. The model is designed for significant reductions in energy consumption and

carbon emissions when compared to homes with standard appliances and mechanical systems.

The Propane Energy Pod includes mechanical systems with high-efficiency amenities, such as

on-demand hot water, professional-grade cooktops, and switch-on fireplaces. According to a

study by Newport Partners, a home built using the Propane Energy Pod model can save

homeowners about $285 in annual energy costs.

Additionally, ORNL has developed a ZEHcor Interior Utility Wall concept. The ZEHcore wall

concept is a pre-fabricated wall to which all kitchen and laundry appliances would be connected,

including major bathroom fixtures. The wall would be built off-site in a controlled environment.

It is designed to reduce hot water distribution losses and enable a high level of integration

between appliances that could not otherwise be accomplished reliably on-site. The ZEHcore

wall could also be integrated with an external foundation heat exchanger.

76

Sources:

1. Whirlpool, August 2011. http://www.whirlpool.co.uk/discover-

whirlpool/sustainability/green-kitchen.content.html

2. Appliance Magazine, June 2011.

Source: http://www.appliancemagazine.com/news.php?article=1497114&zone=0&first=101

3. Images: http://www.treehugger.com/files/2008/03/kitchen-design-whirlpool.php

4. Thomas King. May 2009. “Addressing the Future Energy Challenges Through Innovation.”

Oak Ridge National Laboratory. Presentation available at

http://e2s2.ndia.org/pastmeetings/2009/tracks/Documents/8240.pdf

http://www.whirlpool.co.uk/discover-whirlpool/sustainability/green-kitchen.content.html

http://www.whirlpool.co.uk/discover-whirlpool/sustainability/green-kitchen.content.html

http://www.appliancemagazine.com/news.php?article=1497114&zone=0&first=101

http://www.treehugger.com/files/2008/03/kitchen-design-whirlpool.php

http://e2s2.ndia.org/pastmeetings/2009/tracks/Documents/8240.pdf

BUILDING TECHNOLOGIES OFFICE

DOE/EE-0848 • March 2012 Printed with a renewable-source ink on paper containing at least

50% wastepaper, including 10% post-consumer waste.